Courses

Prof. Naveen Kumar Nishchal

Prof. Naveen Kumar Nishchal
Professor
Department of Physics
M.Sc., Ph.D (IIT Delhi)
Ph: +91-6115 233 027
nkn[*AT]iitp.ac.in
Research Areas
  • Applied Optics (Optical Information Processing, Image Encryption, Watermarking, Digital Holography, Fractional Fourier Transform-based Signal Processing, Correlation-based Optical Pattern Recognition)
Other Interests
  • Papers in Hindi Magazine: 1. N. K. Nishchal, “Digital Holographic Microscope,” Sampark XVI-23 (Dec. 15, 2012). 2. N. K. Nishchal, “Tri-vimiye Doordarshan,” Sampark XV-19 (Oct. 15, 2010). 3. N. K. Nishchal, “Vishwa Ka Sabse Bada Laser,” Sankalp 18 (2007) 19-20. 4. N. K. Nishchal, V. K. Beri, and A. K. Gupta, “Prakashiye Pratikriti Pahchan Me Filter Ka Mahatva,” Sankalp 17 (2006) 23-25. 5. N. K. Nishchal, “Prakashkiye Pratikriti Swikaran,” Sankalp 16 (2005) 7-9. 6. N. K. Nishchal and K. Singh, “Aankik Holography,” Jigyasa 19 (2005) 29-31. 7. N. K. Nishchal and K. Singh, “Optical Kriptography,” Jigyasa 18 (2004) 22-25. 8. N. K. Nishchal and K. Singh, “Lens Dwara Prakashkiye Fourier Rupantaran,” Jigyasa 17 (2003) 36. 9. N. K. Nishchal and J. Behari, “Paryavaran Aur Shaakahar,” Jigyasa 16 (2002) 75. 10. N. K. Nishchal, J. Joseph, and K. Singh, “Wavelet Transform,” Jigyasa 15 (2001) 23
Courses taught at IIT P
  • 1. PH 001 Preparatory Physics – I 2. PH 002 Preparatory Physics – II 3. PH 101 Physics – I (Tutorial) 4. PH 102 Physics II (Theory & Tutorial) 5. PH 110 Physics Laboratory 6. PH 201 Optics and Lasers 7. PH 301 Engineering Optics 8. PH 503 Nanophotonics 9. NT 504 Seminar Course 10. PH 609 Fourier Optics & Holography 11. PH 702 Classical Mechanics & Electrodynamics 12. PH 705 Fourier Optics 13. PH 710 Theory and Applications of Holography
Students
Sr. No. Photo Area of Reasearch Degree
1
Ms. Neha Choudhary (2321PH14, since July 21, 2023)
2
Mr. Sonu Kumar Rao (2321PH04, since Jan. 09, 2023)
3
Mr. Jyoti Bikash Mohapatra (2221PH05, since Jan. 03, 2022)
4
Mr. Akash Pal (2221PH19, since Jan. 03, 2022)
5
Mr. Ram Kumar (2221PH11, since Jan. 03, 2022)
6
Ms. Mansi Baliyan (2121PH22, since July 23, 2021)
7
Mr. Rahul Kumar (2121PH25, since July 23, 2021) Co-Supervisor: Prof. Ayman Alfalou, France
8
Mr. Allarakha Shikder (Jan. 2021)
Former Students
Sr. No. Photo Area of Reasearch Current Position
1
Mr. Avishek Kumar (2018 – 2022) at Electrical Engineering Department, IIT Patna (co-supervision with Dr. Rajib Kumar Jha) [Thesis title: Fusion-based Approaches for Image Dehazing]
2
Mr. Alok Kumar Gupta (2016 – 2021) at Physics Department, IIT Patna [Thesis title: _Investigations on __Quantitative Phase Imaging using __Transport of Intensity Equation_]
3
Mr. Praveen Kumar (2017 – 2021) at Physics Department, IIT Patna [Thesis title: _Investigations on Structured Light to Probe Optical Singularity and its use in Image Encryption_]
4
Ms. Areeba Fatima (2013-2018) at Physics Department, IIT Patna [Thesis: Some Investigations on Phase-retrieval in Optical Asymmetric Cryptosystems]
5
Mr. Dhirendra Kumar (2011-2017) at Physics Department, IIT Patna [Thesis: Investigations on Recognition and Security Techniques for Three-dimensional Objects using Digital Holography]
6
Ms. Isha Mehra (2011-2016) at Physics Department, IIT Patna [Thesis: Investigations on Asymmetric Image Encryption using Optical Transforms]
7
Mr. Sudheesh Kumar Rajput (2010-2014) at Physics Department, IIT Patna [Thesis: Some Optical Image Encryption Techniques based on Amplitude- and Phase-truncation]
Awards & Honours
  • 1. Number of citations: 4,127, h-index: 36, i10 index: 77 (Source: Google Scholar) 2. Program Chair, OPTICA Conference on Digital Holography & 3D Imaging (DH-2025), August 18-21, 2025, Washington, USA 3. Associate Editor, Optics Continuum, OPTICA, USA (2024-) 4. Associate Editor, Optical Engineering, SPIE, USA (2020-) 5. Name appeared in World’s Top 2% Scientists List in Optics by Stanford University, USA (PLOS Biology, Oct. 2020, 2021, 2022, & 2023). 6. Indian Association of Physics Teachers (IAPT) - Dinabandhu Sahu Memorial Award-2022 in recognition of significant contribution to undergraduate physics teaching (Sept. 05, 2022). 7. Best Teacher (Under Graduate), Spring Semester-2020, Physics Department, IIT Patna (Sept. 05, 2020). 8. India Top Cited Author Award-2019 as an author of one of the top 1% most-cited papers in Physics published over the period of 2016-2018, IOP Publishing, UK. A. Fatima, I. Mehra, and N. K. Nishchal, “Optical image encryption using equal modulus decomposition and multiple diffractive imaging,” Journal of Optics 18 (2016) 085701.
Books
    1. N. K. Nishchal, Optical Cryptosystems, IOP Publishing Ltd., Bristol, UK (2019).
      https://iopscience.iop.org/book/978-0-7503-2220-1
    2. A. Fatima and N. K. Nishchal, “Equal modulus decomposition based asymmetric optical cryptosystems,” Chapter 5, Advanced Secure Image Processing for Communications, Ed. Ayman Al Falou, IOP Publishing Ltd. (2018).
    3. A. Fatima and N. K. Nishchal, “Phase retrieval in optical cryptography,” Chapter 3, Cryptographic and Information Security Approaches for Images and Videos, Ed. S. Ramakrishnan, CRC Press (2018).
Publications / Journals / Conferences

  • International Journal:

    1. S. K. Rajput, A. Shikder, N. K. Nishchal, R. Todo, O. Matoba, and Y. Awatsuji, “Holographic acoustic-signal authenticator,” Photonics Research 12 (2024) 2104-2114.
    2. R. Kumar, N. K. Nishchal, and A. Alfalou, “Wavelet-modified segmented phase-only filter for in-plane rotated object recognition,” Physica Scripta 99 (2024) 085538.
    3. R. Kumar, P. Kumar, N. K. Nishchal, and A. Alfalou, “Image authentication with exclusive-OR operated optical vortices,” Journal of Optical Society of America A 41 (2024) 1365-1371.
    4. M. Baliyan and N. K. Nishchal, “Optical cryptography with C-point vector beams,” Optics and Lasers in Engineering 180 (2024) 108337.
    5. S. K. Rao and N. K. Nishchal, “Asymmetric multi-image encoding and hiding scheme with structured fingerprint phase masks using gyrator transform and phase-shifting digital holography,” Journal of Optics 26 (2024) 075701.
    6. A. Pal, Jyothish M., and N. K. Nishchal, “Estimation of distance and rotation with an optical correlator,” IEEE Photonics Technology Letters 36 (2024) 689-692.
    7. A. Shikder, J. B. Mohapatra, and N. K. Nishchal, “Fractional topological charge measurement through optical correlation,” Optics Letters 49 (2024) 2017-2020.
    8. M. Baliyan and N. K. Nishchal, “Determining topological charge of Bessel-Gaussian beams using modified Mach-Zehnder interferometer,” MDPI Photonics 11 (2024) 263.
    9. A. Shikder, S. K. Rao, P. Kumar, and N. K. Nishchal, “Binary image encryption with QR code-encoded optical beam having array of vortices,” Journal of Optical Society of America A 41 (2024) A73-A82.
    10. M. Baliyan, P. Kumar, and N. K. Nishchal, “Image encryption through dualpass modulated azimuthally polarized vector field,” IEEE Photonics Technology Letters 36 (2024) 313-316.
    11. S. K. Rao, N. K. Nishchal, and A. Alfalou, “Optical asymmetric image encryption using vectorial light field encoding,” Optics Communications 554 (2024) 130097.
    12. R. Kumar, A. Shikder, N. K. Nishchal, and A. Alfalou, “Topological charge identification of vortex beams through optical correlation,” IEEE Photonics Technology Letters 35 (2023) 1315-1318.
    13. S. K. Rao and N. K. Nishchal, “Optical asymmetric cryptosystem for multiple image encryption through vector field encoding,” Applied Physics B: Lasers and Optics 129 (2023) 170.
    14. R. Kumar, N. K. Nishchal, and A. Alfalou, “Improving the false alarm capability of the extended maximum average correlation height filter,” MDPI Photonics 10 (2023) 1096.
    15. M. Baliyan, A. Shikder, and N. K. Nishchal, “Generation of structured light beams by a dual phase modulation with a single spatial light modulator,” Physica Scripta 98 (2023) 105528.
    16. A. Shikder and N. K. Nishchal, “Image encryption using binary polarization states of light beam,” Scientific Reports 13 (2023) 14028.
    17. M. Baliyan and N. K. Nishchal, “Generating scalar and vector modes of Bessel beams utilizing holographic axicon phase with spatial light modulator,” Journal of Optics 25 (2023) 095702.
    18. A. Shikder and N. K. Nishchal, “Generation of optical vortex lattices by in-line phase modulation with partially coherent light,” Journal of Optical Society of America A 40 (2023) 1231-1236.
    19. I. Mehra and N. K. Nishchal, “Fingerprint image encryption using phase retrieval algorithm in gyrator wavelet transform domain using QR decomposition,” Optics Communications 533 (2023) 129265.
    20. A. Shikder and N. K. Nishchal, “Measurement of fractional topological charge of optical vortex beam through interference fringe dislocation,” Applied Optics 62 (2023) D58-D67.
    21. A. Shikder, P. Kumar, and N. K. Nishchal, “Image encryption by structured phase encoding and its effectiveness in turbulent medium,” IEEE Photonics Technology Letters 35 (2023) 128-131.
    22. P. Kumar, N. K. Nishchal, T. Omatsu, and A. S. Rao, “Self-referenced interferometry for single-shot detection of vector-vortex beams,” Scientific Reports 12 (2022) 17253.
    23. P. Kumar, N. K. Nishchal, and A. AlFalou, “Color image encryption using vectorial field through a compact optical set-up,” Journal of Optics 24 (2022) 064017.
    24. P. Kumar, N. K. Nishchal, and A. AlFalou, “Controllable optical vortex array for image encoding,” IEEE Photonics Technology Letters 34 (2022) 521-524.
    25. P. Kumar, N. K. Nishchal, T. Omatsu, and A. S. Rao, “Optical vortex array for two-dimensional exclusive-OR operation,” Applied Physics B: Lasers and Optics 128 (2022) 98.
    26. P. Kumar and N. K. Nishchal, “Phase response optimization of a liquid crystal spatial light modulator with partially coherent light,” Applied Optics 60 (2021) 10795-10801.
    27. A. Kumar, R. K. Jha, and N. K. Nishchal, “A multi-exposure fusion framework for contrast enhancement of hazy images employing dynamic stochastic resonance,” Journal of Visual Communication and Image Representation 81 (2021) 103376.
    28. A. Kumar, R. K. Jha, and N. K. Nishchal, “Dynamic stochastic resonance and image fusion based model for quality enhancement of dark and hazy images,” Journal of Electronic Imaging 30 (2021) 063008.
    29. P. Kumar and N. K. Nishchal, “Formation of singular light fields using phase calibrated spatial light modulator,” Optics and Lasers in Engineering 146 (2021) 106720.
    30. A. Kumar, R. K. Jha, and N. K. Nishchal, “A joint Gamma correction and multi-resolution fusion scheme for enhancing haze degraded images,” Optical Engineering 60 (2021) 063103.
    31. A. Kumar, R. K. Jha, and N. K. Nishchal, “An improved Gamma correction model for image dehazing in a multi-exposure fusion framework,” Journal of Visual Communication and Image Representation 78 (2021) 103122.
    32. A. K. Gupta, P. Kumar, N. K. Nishchal, and A. Al Falou, “Polarization-encoded fully-phase encryption using transport of intensity equation,” MDPI Electronics 10 (2021) 00969.
    33. P. Kumar and N. K. Nishchal, “Array formation of optical vortices using in-line phase modulation,” Optics Communications 493 (2021) 127020.
    34. A. K. Gupta and N. K. Nishchal, “Low-light phase imaging using in-line digital holography and transport of intensity equation,” Journal of Optics 23 (2021) 025701.
    35. P. Kumar, A. Fatima, and N. K. Nishchal, “Arbitrary vector beam encoding using single modulation for information security for information security applications,” IEEE Photonics Technology Letters 33 (2021) 243-246.
    36. P. Kumar, S. K. Pal, N. K. Nishchal, and P. Senthilkumaran, “Formation of polarization singularity lattice through dual-phase modulation,” Journal of Optics 22 (2020) 115701.
    37. A. K. Gupta, R. Mahendra, and N. K. Nishchal, “Single-shot phase imaging based on transport of intensity equation,” Optics Communications 477 (2020) 126347.
    38. P. Kumar, S. K. Pal, N. K. Nishchal, and P. Senthilkumaran, “Non-interferometric technique to realize vector beams embedded with polarization singularities,” Journal of Optical Society of America A 37 (2020) 1043-1052.
    39. A. K. Gupta, A. Fatima, N. K. Nishchal, and T. Nomura, “Phase imaging based on modified transport of intensity equation using liquid crystal variable retarder with partial incoherent illumination,” Optical Review 27 (2020) 142-148.
    40. A. K. Gupta, N. K. Nishchal, and P. P. Banerjee, “Transport of intensity equation based photon counting phase imaging,” OSA Continuum 3 (2020) 236-245.
    41. P. Kumar and N. K. Nishchal, “Self-referenced interference of laterally displaced vortex beams for topological charge determination,” Optics Communications 459 (2020) 125000.
    42. P. Kumar and N. K. Nishchal, “Self-referenced spiral interferogram using modified lateral shearing Mach-Zehnder interferometer,” Applied Optics 58 (2019) 6827-6833.
    43. P. Kumar and N. K. Nishchal, “Modified Mach-Zehnder interferometer for determining high-order topological charge of Laguerre-Gaussian vortex beams,” Journal of Optical Society of America A 36 (2019) 1447-1455.
    44. P. Kumar, A. Fatima, and N. K. Nishchal, “Image encryption using phase-encoded exclusive-OR operations with incoherent illumination,” Journal of Optics 21 (2019) 065701.
    45. P. Kumar and N. K. Nishchal, “Enhanced exclusive-OR and quick response code-based image encryption through incoherent illumination,” Applied Optics 58 (2019) 1408-1412.
    46. A. Kumar and N. K. Nishchal, “Quick response code and interference-based optical asymmetric cryptosystem,” Journal of Information Security and Applications 45 (2019) 35-43.
    47. T. Pitkaaho, V. Pitkakangas, M. Niemela, S. K. Rajput, N. K. Nishchal, and T. J. Naughton, “Space-variant video compression and processing in digital holographic microscopy sensor networks with application to potable water monitoring,” Applied Optics 57 (2018) E190-E198.
    48. A. Kumar, A. Fatima, and N. K. Nishchal, “An optical Hash function construction based on equal modulus decomposition for authentication verification,” Optics Communications 428 (2018) 07-14.
    49. A. Fatima and N. K. Nishchal, “Image authentication using vector beam with sparse phase information,” Journal of Optical Society of America A 35 (2018) 1053-1062.
    50. Yatish, A. Fatima and N. K. Nishchal, “Optical image encryption using triplet of functions,” Optical Engineering 57 (2018) 033103.
    51. A. Fatima and N. K. Nishchal, “Optical image security using Stokes polarimetry of spatially variant polarized beam,” Optics Communications 417 (2018) 30-36.
    52. I. Mehra, A. Fatima and N. K. Nishchal, “Gyrator wavelet transform,” IET Image Processing 12 (2018) 432-437.
    53. R. Kumar, B. Bhaduri, and N. K. Nishchal, “Nonlinear QR code based optical image encryption using spiral phase transform, equal modulus decomposition and singular value decomposition,” Journal of  Optics 20 (2018) 015701.
    54. S. K. Rajput and N. K. Nishchal, “Optical asymmetric cryptosystem based on photon counting and phase-truncated Fresnel transforms,” Journal of Modern Optics 64 (2017) 878-886.
    55. S. K. Rajput and N. K. Nishchal, “Optical double image security using random phase fractional Fourier domain encoding and phase retrieval algorithm,” Optics Communications 388 (2017) 38-46.
    56. D. Kumar and N. K. Nishchal, “Synthesis and reconstruction of multi-plane phase-only Fresnel holograms,” Optik 127 (2016) 12069-12077.
    57. A. Fatima and N. K. Nishchal, “Discussion on comparative analysis and a new attack on optical asymmetric cryptosystem,” Journal of Optical Society of America A 33 (2016) 2034-2040.
    58. B. Javidi, A. Carnicer, M. Yamaguchi, T. Nomura, E. Perez-Cabre, M. S. Millan, N. K. Nishchal, R. Torroba, J. F. Barrera, W. He, X. Peng, A. Stern, Y. Rivenson, A. Alfalou, C. Brosseau, C. Guo, J. T. Sheridan, G. Situ, M. Naruse, T. Matsumoto, I. Juvells, E. Tajahuerce, J. Lancis, W. Chen, X. Chen, P. W. H. Pinkse, A. P. Mosk, and A. Markman, “Roadmap on Optical Security,” Journal of Optics 18 (2016) 083001.
    59. A. Fatima, I. Mehra, and N. K. Nishchal, “Optical asymmetric cryptosystem using equal modulus decomposition and multiple diffractive imaging,” Journal of Optics 18 (2016) 085701.
    60. D. Kumar and N. K. Nishchal, “Three-dimensional object recognition using joint fractional Fourier transform correlators with the help of digital Fresnel holography,” Optik 126 (2015) 2690-2695.
    61. I. Mehra and N. K. Nishchal, “Optical asymmetric image encryption using gyrator wavelet transform,” Optics Communications 354 (2015) 344-352.
    62. D. Kumar and N. K. Nishchal, “Recognition of three-dimensional objects using joint fractional correlator and nonlinear joint fractional correlator with the help of digital Fresnel holography; A comparative study,” Optical Review 22 (2015) 256-263.
    63. I. Mehra, K. Singh, A. K. Agarwal, U. Gopinathan, and N. K. Nishchal, “Encrypting digital hologram of three-dimensional object using diffractive imaging,” Journal of Optics 17 (2015) 035707.
    64. S. K. Rajput, D. Kumar, and N. K. Nishchal, “Optical encryption system based on phase mask multiplexing and photon counting imaging for multiple image authentication and digital hologram security,” Applied Optics 54 (2015) 1657-1666.
    65. I. Mehra and N. K. Nishchal, “Optical asymmetric watermarking using modified wavelet fusion and diffractive imaging,” Optics & Lasers in Engineering 68 (2015) 74-82.
    66. I. Mehra and N. K. Nishchal, “Wavelet-based image fusion for securing multiple images through asymmetric keys,” Optics Communications 335 (2015) 153-160.
    67. S. K. Rajput, D. Kumar, and N. K. Nishchal, “Photon counting imaging and polarized light encoding for secure image verification and hologram watermarking,” Journal of Optics 16 (2014) 125406.
    68. S. K. Rajput and N. K. Nishchal, “An optical encryption and authentication scheme using asymmetric keys,” Journal of the Optical Society of America A 31 (2014) 1233-1238.
    69. I. Mehra and N. K. Nishchal, “Image fusion using wavelet transform and its application to asymmetric cryptosystem and hiding,” Optics Express 22 (2014) 5474-5482.
    70. I. Mehra and N. K. Nishchal, “Asymmetric cryptosystem for securing multiple images using two beam interference phenomenon,” Optics and Laser Technology 60 (2014) 1-7.
    71. S. K. Rajput and N. K. Nishchal, “Fresnel domain nonlinear image encryption scheme based on Gerchberg-Saxton phase retrieval algorithm,” Applied Optics 53 (2014) 418-425.
    72. I. Mehra, S. K. Rajput, and N. K. Nishchal, “Cryptanalysis of an image encryption scheme based on joint transform correlator with amplitude- and phase-truncation approach,” Optics & Lasers in Engineering 52 (2014) 167-173.
    73. S. K. Rajput and N. K. Nishchal, “Known-plaintext attack on encryption domain independent optical asymmetric cryptosystem,” Optics Communications 309 (2013) 231-235.
    74. S. K. Rajput and N. K. Nishchal, “Image encryption using polarized light encoding and amplitude- and phase-truncation in Fresnel domain,” Applied Optics 52 (2013) 4343-4352.
    75. I. Mehra, S. K. Rajput, and N. K. Nishchal, “Collision in Fresnel domain asymmetric cryptosystem using phase truncation and authentication verification,” Optical Engineering 52 (2013) 028202.
    76. S. K. Rajput and N. K. Nishchal, “Known-plaintext attack-based optical cryptosystem using phase-truncated Fresnel transform,” Applied Optics 52 (2013) 871-878.
    77. S. K. Rajput and N. K. Nishchal, “Asymmetric color cryptosystem that uses polarization selective diffractive optical element and structured phase mask,” Applied Optics 51 (2012) 5377-5386.
    78. S. K. Rajput and N. K. Nishchal, “Image encryption based on interference that uses fractional Fourier domain asymmetric keys,” Applied Optics 51 (2012) 1446-1452.
    79. S. K. Rajput and N. K. Nishchal, “Image encryption and authentication verification scheme using fractional nonconventional joint transform correlator,” Optics & Lasers in Engineering 50 (2012) 1474-1483.
    80. N. K. Nishchal, “Hierarchical encrypted image watermarking using fractional Fourier domain random phase encoding,” Optical Engineering 50 (2011) 097003.
    81. N. K. Nishchal and T. J. Naughton, “Flexible optical encryption with multiple users and multiple security levels,” Optics Communications 284 (2011) 735-739.
    82. S. Goyal, N. K. Nishchal, V. K. Beri, and A. K. Gupta, “Wavelet modified maximum average correlation height filter for out-of-plane rotation invariance,” Optik 120 (2009) 62-67.
    83. A. Bhagatji, N. K. Nishchal, A. K. Gupta, and B. P. Tyagi, “Extended fractional wavelet joint transform correlator,” Optics Communications 281 (2008) 44-48.
    84. R. B. Yadav, N. K. Nishchal, A. K. Gupta, and V. K. Rastogi, “Retrieval and classification of objects using generic Fourier, Legendre moment, and wavelet Zernike moment descriptors and recognition using joint transform correlator,” Optics & Laser Technology 40 (2008) 517-527.
    85. A. Aran, N. K. Nishchal, V. K. Beri, and A. K. Gupta, “Log-polar transform-based wavelet-modified maximum average correlation height filter for distortion-invariant target recognition,” Optics & Lasers in Engineering 46 (2008) 34-41.
    86. A. Bhagatji, N. K. Nishchal, A. K. Gupta, and B. P. Tyagi, “Wavelet-modified fringe-adjusted joint transform correlator,” Optics & Laser Technology 40 (2008) 99-112.
    87. A. Aran, N. K. Nishchal, V. K. Beri, and A. K. Gupta, “Log-polar transform-based wavelet-modified maximum average correlation height filter for distortion invariance in a hybrid digital-optical correlator,” Applied Optics 46 (2007) 7970-7977.
    88. R. B. Yadav, N. K. Nishchal, A. K. Gupta, and V. K. Rastogi, “Retrieval and classification of shape-based objects using Fourier, generic Fourier, and wavelet Fourier descriptors technique; A comparative study,” Optics & Lasers in Engineering 45 (2007) 695-708.
    89. A. Bhagatji, N. K. Nishchal, V. K. Beri, and A. K. Gupta, “Influence of perturbations in a hybrid digital-optical correlator,” Optics & Lasers in Engineering 45 (2007) 1-11.
    90. S. Goyal, N. K. Nishchal, V. K. Beri, and A. K. Gupta, “Wavelet-modified maximum average correlation height filter for rotation invariance that uses chirp encoding in a hybrid digital-optical correlator,” Applied Optics 45 (2006) 4850-4857.
    91. N. K. Nishchal, S. Goyal, A. Aran, V. K. Beri, and A. K. Gupta, “Binary differential joint transform correlator based on a ferroelectric liquid crystal electrically addressed spatial light modulator,” Optical Engineering 45 (2006) 026401.
    92. N. K. Nishchal, G. Unnikrishnan, J. Joseph, and K. Singh, “Optical information security using Fourier and fractional Fourier domain techniques,” SPIE’s International Technical Group Newsletter 16.1 (2005) 4.
    93. N. K. Nishchal, J. Joseph, and K. Singh, “Fully phase encryption using digital holography,” Optical Engineering 43 (2004) 2959-2966.
    94. N. K. Nishchal, J. Joseph, and K. Singh, “Fully phase-based encryption using fractional order Fourier domain random phase encoding; Error analysis,” Optical Engineering 43 (2004) 2266-2273.
    95. N. K. Nishchal, J. Joseph, and K. Singh, “Securing information using fractional Fourier transform in digital holography,” Optics Communications 235 (2004) 253-259.
    96. N. K. Nishchal, J. Joseph, and K. Singh, “Fully phase encrypted memory using cascaded extended fractional Fourier transform,” Optics & Lasers in Engineering 42 (2004) 141-151.
    97. N. K. Nishchal, G. Unnikrishnan, J. Joseph, and K. Singh, “Optical encryption using localized fractional Fourier transform,” Optical Engineering 42 (2003) 3566-3571.
    98. N. K. Nishchal, J. Joseph, and K. Singh, “Optical encryption using cascaded extended fractional Fourier transform,” Optical Memory & Neural Networks 12 (2003) 139-145.
    99. N. K. Nishchal, J. Joseph, and K. Singh, “Fully phase encryption using fractional Fourier transform,” Optical Engineering 42 (2003) 1583-1588.
    100. N. K. Nishchal, J. Joseph, and K. Singh, “Optical phase encryption by phase contrast using electrically addressed spatial light modulator,” Optics Communications 217 (2003) 117-122.

    National Journal:

    1. J. B. Mohapatra, Jyothish M., and N. K. Nishchal, “Object recognition under bad weather conditions with wavelet-modified logarithmic fringe-adjusted joint transform correlator,” Journal of Optics (Springer) 53 (2024) (in press).
    2. D. Manchaiah, R. Kumar, V. S. Chauhan, P. Kumar, N. K. Nishchal, and R. K. Easwaran, “Impact of higher-order Laguerre-Gaussian modes on electromagnetically induced transparency resonances in 87Rb atomic vapor medium,” Journal of Optics (Springer) 53 (2024) (in press).
    3. A. Shikder, P. Kumar, N. K. Nishchal, and K. Singh, “Types of structured light beams and their applications in optical cryptography: A review,” Asian Journal of Physics 32 (2023) 369-383.
    4. R. Kumar, N. K. Nishchal, and K. Singh, “Combining digital holography and transport of intensity equation for quantitative phase imaging; a review,” Asian Journal of Physics 31 (2022) 1117-1127.
    5. A. K. Gupta and N. K. Nishchal, “A composite method of transport of intensity equation for the recovery of broad range of spatial frequencies,” Journal of Optics (Springer) 51 (2022) 605-612.
    6. A. Kumar, R. K. Jha, and N. K. Nishchal, “An image dehazing method employing iterative Gamma correction in a multi-resolution fusion framework,” Asian Journal of Physics 31 (2022) 17-24.
    7. P. Kumar and N. K. Nishchal, “Realizing singular beams through dual-phase modulation,” Asian Journal of Physics 30 (2021) 1355-1364.
    8. N. K. Nishchal, “Use of vector beam in image encryption; A review,” Asian Journal of Physics 30 (2021) 1007-1012.
    9. A. Kumar, R. K. Jha, and N. K. Nishchal, “An image dehazing method based on chromaticity guided regularization,” Asian Journal of Physics 30 (2021) 759-768.
    10. P. Kumar, N. K. Nishchal, and K. Singh, “Role of self-referenced interferometry in measuring the orbital angular momentum of optical vortices: A review,” Asian Journal of Physics 29 (2020) 835-852.
    11. A. K. Gupta and N. K. Nishchal, “Transport of intensity equation for phase imaging; A review,” Asian Journal of Physics 28 (2019) 777-786.
    12. A. Fatima and N. K. Nishchal, “Photon-counting and sparsity-based optical authentication and verification schemes,” Asian Journal of Physics 27 (2018) 597-602.
    13. A. Fatima and N. K. Nishchal, “Plasmonics: A new paradigm for information security,” Asian Journal of Physics 25 (2016) 59-64.
    14. D. Kumar and N. K. Nishchal, “Watermarking of phase-only Fresnel hologram using symmetrical 3D modified Gerchberg-Saxton algorithm,” Asian Journal of Physics 24 (2015) 1425-1429.
    15. D. Kumar and N. K. Nishchal, “Three-dimensional object recognition with joint fractional Fourier transform correlator using digital Fresnel holography,” Asian Journal of Physics 23 (2014) 527-534.
    16. S. K. Rajput and N. K. Nishchal, “Optical asymmetric cryptosystems: A review,” Asian Journal of Physics 23 (2014) 473-490.
    17. I. Mehra and N. K. Nishchal, “Image hiding using joint transform correlator and modified Gerchberg-Saxton phase retrieval algorithm,” Asian Journal of Physics 22 (2013) 167-174.
    18. S. K. Rajput and N. K. Nishchal, “Security enhanced asymmetric cryptosystem in Fresnel domain,” Asian Journal of Physics 22 (2013) 117-126.
    19. N. K. Nishchal, “Wavelet-modified MACH filter and log-polar transform-based wavelet-modified MACH filter for distortion invariant pattern identification; A comparative study,” Asian Journal of Physics 19 (2010) 87-93.
    20. N. K. Nishchal, “Optical image watermarking using fractional Fourier transform,” Journal of Optics (Springer-India) 38 (2009) 22-28.
    21. R. B. Yadav, N. K. Nishchal, A. K. Gupta, and V. K. Rastogi, “Vehicular shape-based object classification using Fourier descriptor technique,” Journal of Scientific & Industrial Research 68 (2009) 484-495.                                                                                                               
    22. V. K. Beri, N. K. Nishchal, A. K. Gupta, and V. K. Rastogi, “Design parameters of a hybrid correlator,” Indian Journal of Pure & Applied Physics 46 (2008) 844-851.
    23. A. Bhagatji, N. K. Nishchal, A. K. Gupta, and B. P. Tyagi, “Fractional order Fourier transform-based fringe-adjusted joint transform correlator,” Indian Journal of Pure & Applied Physics 46 (2008) 176-186.
    24. S. Goyal, N. K. Nishchal, V. K. Beri, and A. K. Gupta, “Complex data mapping on a binary ferroelectric liquid crystal electrically addressed spatial light modulator for target recognition,” Indian Journal of Pure & Applied Physics 45 (2007) 647-653.
    25. N. K. Nishchal, “Optical techniques for information security,” DRDO Science Spectrum; A Compendium of National Science Day Orations (2005) 125-139.
    26. N. K. Nishchal, J. Joseph, and K. Singh, “Data security using optoelectronic techniques,” Physics Teacher 45 (2003) 71-75.
    27. N. K. Nishchal, J. Joseph, and K. Singh, “Phase image encryption in double random fractional Fourier domain encoding using phase contrast technique,” Asian Journal of Physics 11 (2002) 47-52.
    28. N. K. Nishchal, J. Joseph, and K. Singh, “A multichannel optical correlator,” Asian Journal of Physics 11 (2002) 53-56.
    29. G. S. Khan, N. K. Nishchal, J. Joseph, and K. Singh, “Fractional Fourier transform and its applications: A bibliographic review,” Asian Journal of Physics 10 (2001) 251-299.
    30. N. K. Nishchal, R. Paul Raj, U. S. Mishra, S. K. Sahu, and R. Lochan, “Electromagnetic field in and around the campus of Jawaharlal Nehru University, New Delhi,” Indian Journal of Biochemistry & Biophysics 36 (1999) 374-378.

    SPIE Conference Proceedings:

    1. A. K. Gupta and N. K. Nishchal, “Transport of intensity equation for low-light quantitative phase imaging and security applications,” Proc. SPIE 11898 (2021) 118980W [Invited paper].
    2. N. K. Nishchal, “Optical asymmetric encryption schemes and attack analysis,” Proc. SPIE 10795 (2018) 1079509.
    3. A. Fatima and N. K. Nishchal, “Simultaneous authentication verification of multiple secured images using joint transform correlation approach,” Proc. SPIE 10795 (2018) 1079508.
    4. I. Mehra and N. K. Nishchal, “Double image encryption using gyrator wavelet transform,” Proc. SPIE 9654 (2015) 96542D.
    5. S. K. Rajput and N. K. Nishchal, “Optical asymmetric cryptosystem using polarized light,” Proc. SPIE 8855 (2013) 885503.
    6. S. K. Rajput and N. K. Nishchal, “Known-plaintext attack on asymmetric cryptosystem,” Proc. SPIE 8855 (2013) 88550U.
    7. S. K. Rajput and N. K. Nishchal, “Multiple image encryption based on known-plaintext attack and modified G-S phase retrieval algorithm,” Proc. SPIE 8769 (2013) 87690X.
    8. S. K. Rajput and N. K. Nishchal, “Fractional domain asymmetric cryptosystem and cryptanalysis,” Proc. SPIE 8769 (2013) 87691Y [Invited paper].
    9. A. K. Gupta, N. K. Nishchal, and V. K. Beri, “A hybrid digital-optical correlator for automatic target recognition,” Proc. SPIE 6574 (2007) 657406.
    10. A. Bhagatji, N. K. Nishchal, A. K. Gupta, and B. P. Tyagi, “Wavelet-modified fringe-adjusted joint transform correlator,” Proc. SPIE 6405 (2006) 640513.
    11. A. K. Gupta, N. K. Nishchal, and V. K. Beri, “Genetic algorithm based composite wavelet matched filter for 0 to 360° out-of-plane rotations for target recognition,” Proc. SPIE 6234 (2006) 623409.
    12. N. K. Nishchal, J. Joseph, and K. Singh, “Fully phase encrypted memory using cascaded extended fractional Fourier transform,” Proc. SPIE 5202 (2003) 106-113.
    13. K. Singh and N. K. Nishchal, “Fractional Fourier transform; applications in information optics,” Proc. SPIE 4929 (2002) 34-48.
    14. K. Singh, G. Unnikrishnan, and N. K. Nishchal, “Photorefractive optical processing for data security,” Proc. SPIE 4803 (2002) 205-219.
Presentations
  • 1. N. K. Nishchal, “Generation and detection of structured light beams and its applications,” XLVII OSI Symposium – International Conference on Advances in Optics and Photonics Instrumentation (OPTOIn-2024), Oct. 23-25, 2024, CSIO Chandigarh [Invited]. 2. R. Kumar, A. Pal, N. K. Nishchal, and A. Alfalou, “Multi-target detection through wavelet-modified maximum average correlation height filter,” OPTICA Frontiers in Optics Meeting on Information Acquisition, Processing and Display (FiO + LS-2024), Sept. 23-26, 2024, Denver, Colorado, USA. 3. A. Pal, R. Kumar, Jyothish M., and N. K. Nishchal, “In-plane rotation estimation through composite filter synthesis and log-polar mapping,” OPTICA Frontiers in Optics Meeting on Information Acquisition, Processing and Display (FiO + LS-2024), Sept. 23-26, 2024, Denver, Colorado, USA. 4. S. K. Rao, R. Kumar, N. K. Nishchal, and A. Alfalou, “Optical image encryption using modified GS algorithm and DNA encoding,” OPTICA Frontiers in Optics Meeting on Information Acquisition, Processing and Display (FiO + LS-2024), Sept. 23-26, 2024, Denver, Colorado, USA. 5. M. Baliyan and N. K. Nishchal, “Controlled generation of Poincare Bessel-Gaussian beams,” OPTICA Frontiers in Optics Meeting on Information Acquisition, Processing and Display (FiO + LS-2024), Sept. 23-26, 2024, Denver, Colorado, USA. 6. R. Kumar and N. K. Nishchal, “Phase imaging from X-ray intensity images using transport of intensity equation,” OPTICA Digital Holography and Three-Dimensional Imaging (DH-2024), W4A.23, June 03-06, 2024, Paestum, ITALY. 7. S. K. Rao and N. K. Nishchal, “Optical asymmetric colorimage encryption using vector light field encoding,” OPTICA Digital Holography and Three-Dimensional Imaging (DH-2024), W4A.36, June 03-06, 2024, Paestum, ITALY. 8. J. B. Mohapatra, R. Kumar, Jyothish M., and N. K. Nishchal, “Chirp-encoded fringe-adjusted joint transform correlator for 3D object recognition using Fresnel holography,” OPTICA Digital Holography and Three-Dimensional Imaging (DH-2024), W4A.12, June 03-06, 2024, Paestum, ITALY. 9. A. Shikder and N. K. Nishchal, “Multiple image encryption using radial modes of light beam,” OPTICA Digital Holography and Three-Dimensional Imaging (DH-2024), W4A.35, June 03-06, 2024, Paestum, ITALY. 10. N. K. Nishchal, “Information security using the properties of optical vortex lattice,” OPTICA Digital Holography and Three-Dimensional Imaging (DH-2024), M4B.6, June 03-06, 2024, Paestum, ITALY [Invited]. 11. N. K. Nishchal, “Vortex beam array for securing information,” International Conference on Sustainanble Nanomaterials Integration and Oraganization for Energy and Environment (iSNIOE2), March 20-23, 2024, Shiv Nadar University, Greater Noida [Invited]. 12. A. Shikder and N. K. Nishchal, “Application of optical vortex in image encryption,” XLVI OSI Symposium-International Conference on Optics, Photonics & Quantum Information (OPTIQ-2023), Dec. 11-13, 2023, CUSAT Cochin [Invited]. (Couldn’t present) 13. A. Shikder, J. B. Mohapatra, and N. K. Nishchal, “Fractional topological charge measurement of optical vortex beam using joint transform correlator,” XLVI OSI Symposium-International Conference on Optics, Photonics & Quantum Information (OPTIQ-2023), Dec. 11-13, 2023, CUSAT Cochin. 14. J. B. Mohapatra, A. Pal, M. Jyothish, and N. K. Nishchal, “Object detection in foggy and hazy conditions,” XLVI OSI Symposium-International Conference on Optics, Photonics & Quantum Information (OPTIQ-2023), Dec. 11-13, 2023, CUSAT Cochin. 15. A. Pal, J. B. Mohapatra, Joythish M., and N. K. Nishchal, “Binary differential joint transform correlator based rotation angle estimation,” Sixth IEEE International Workshop on Recent Advances in Photonics (WRAP-2023), Dec. 07-09, 2023, IIIT Allahabad. 16. M. Baliyan and N. K. Nishchal, “Generating multiple polarization singularities through non-interferometric technique,” Sixth IEEE International Workshop on Recent Advances in Photonics (WRAP-2023), Dec. 07-09, 2023, IIIT Allahabad. 17. S. K. Rao and N. K. Nishchal, “Vectorial light field encoding for asymmetric encryption,” Sixth IEEE International Workshop on Recent Advances in Photonics (WRAP-2023), Dec. 07-09, 2023, IIIT Allahabad. 18. A. Shikder, S. K. Rao, P. Kumar, and N. K. Nishchal, “Image encoding using dual phase modulation,” Sixth IEEE International Workshop on Recent Advances in Photonics (WRAP-2023), Dec. 07-09, 2023, IIIT Allahabad. 19. N. K. Nishchal, “Optical cryptography through optical vortex,” Topical Conference to Commemorate the Birth Centenary of Professor Manoranjan De (IConTop-2023), Nov. 24-25, 2023, Calcutta University, Kolkata [Invited]. 20. R. Kumar, A. Shikder, N. K. Nishchal, A. AlFalou, “Recognition of optical vortex modes assisted by a MACH filter,” Topical Conference to Commemorate the Birth Centenary of Professor Manoranjan De (IConTop-2023), Nov. 24-25, 2023, Calcutta University, Kolkata. 21. A. Shikder and N. K. Nishchal, “Information encoding through binary polarization states,” Topical Conference to Commemorate the Birth Centenary of Professor Manoranjan De (IConTop-2023), Nov. 24-25, 2023, Calcutta University, Kolkata. 22. R. Kumar, N. K. Nishchal, and A. AlFalou, “Modified extended maximu average correlation height filter for target identification,” OPTICA Frontiers in Optics: Information Acquisition, Processing and Display (FiO7-2023), Oct. 09-12, 2023, Tacoma, Washington, USA. 23. M. Baliyan and N. K. Nishchal, “Optical image encryption using non-separable vector beams,” OPTICA Frontiers in Optics: Information Acquisition, Processing and Display (FiO7-2023), Oct. 09-12, 2023, Tacoma, Washington, USA. 24. A. Shikder and N. K. Nishchal, “Generation of controllable optical vortex array by in-line phase modulation with a light emitting diode,” OPTICA Frontiers in Optics: Information Acquisition, Processing and Display (FiO7-2023), Oct. 09-12, 2023, Tacoma, Washington, USA. 25. M. Baliyan and N. K. Nishchal, “Generation of vector Bessel modes using spiral axicon hologram,” OPTICA Digital Holography and Three-Dimensional Imaging (DH-2023), Aug. 14-17, 2023, Boston, Massachusetts, USA. 26. S. K. Rao and N. K. Nishchal, “Fully-phase image encryption and watermarking using structured phase masks,” OPTICA Digital Holography and Three-Dimensional Imaging (DH-2023), Aug. 14-17, 2023, Boston, Massachusetts, USA. 27. A. Shikder and N. K. Nishchal, “Generation of vector vortex beam using partially coherent light,” OPTICA Digital Holography and Three-Dimensional Imaging (DH-2023), Aug. 14-17, 2023, Boston, Massachusetts, USA. 28. M. Baliyan and N. K. Nishchal, “Generation of scalar beams fully manipulated in amplitude and wavefront,” 8th Int’l. Conference on Women in Physics (ICWIP-2023), Homi Bhabha Centre for Science Education (HBCSE), Mumbai, July 09-14, 2023. 29. A. Shikder, R. Kumar, N. K. Nishchal, and A. AlFalou, “Optical vortex lattice-based image encoding,” International Conference on Photonics (PHOTONICS-2023), IISc Bangalore, July 05-08, 2023. 30. A. Shikder and N. K. Nishchal, “Optical image encryption with structured light,” International Conference on Complexity and Nonlinear Dynamics in Science, Technology, Engineering & Mathematics, IIT Hyderabad, June 05-07, 2023 [Invited]. 31. J. B. Mohapatra, A. Pal, J. Jojy, and N. K. Nishchal, “Wavelet-modified logarithmic fringe-adjusted joint transform correlator,” International Conference on Complexity and Nonlinear Dynamics in Science, Technology, Engineering & Mathematics, IIT Hyderabad, June 05-07, 2023. 32. A. Pal, J. B. Mohapatra, J. Jojy, and N. K. Nishchal, “Log-polar mapped phase-only filter for distortion-invariant target identification,” Indo-French Conference on Frontiers in Photonics and Metamaterials (IFCFPM-2023), Mahindra University, Hyderabad, April 21-22, 2023. 33. A. Shikder and N. K. Nishchal, “Fractional topological charge measurement of optical vortex beam using spiral interferometer,” Indo-French Conference on Frontiers in Photonics and Metamaterials (IFCFPM-2023), Mahindra University, Hyderabad, April 21-22, 2023. 34. A. Shikder and N. K. Nishchal, “Binary image encoding through optical vortex lattice,” Indo-French Conference on Frontiers in Photonics and Metamaterials (IFCFPM-2023), Mahindra University, Hyderabad, April 21-22, 2023. 35. A. Shikder and N. K. Nishchal, “Optical vortices-based image encryption,” International Seminar on Atomic Process, Laser, Nano-material and Terahertz Technology for Optical Fiber Communication (LNTOFC-2023), M L S College, Madhubani, Feb. 09-10, 2023 [Invited]. 36. P. Kumar and N. K. Nishchal, “Image encryption through structured light,” XLV Annual Symposium of OSI as Conference on Optics, Photonics, and Quantum Optics (COPaQ-2022), IIT Roorkee, Nov. 10-13, 2022 [Invited]. 37. M. Baliyan and N. K. Nishchal, “Generation of cylindrical vector beam using non-interferometric dual phase modulation,” XLV Annual Symposium of OSI as Conference on Optics, Photonics, and Quantum Optics (COPaQ-2022), IIT Roorkee, Nov. 10-13, 2022. 38. R. Kumar, A. Shikder, N. K. Nishchal, and A. AlFalou, “Orbital angular momentum mode identification of vortex beam using optical correlation,” XLV Annual Symposium of OSI as Conference on Optics, Photonics, and Quantum Optics (COPaQ-2022), IIT Roorkee, Nov. 10-13, 2022. 39. A. Shikder and N. K. Nishchal, “Generation of higher order array of vortices through in-line wavefront shaping using spatial light modulator,” XLV Annual Symposium of OSI as Conference on Optics, Photonics, and Quantum Optics (COPaQ-2022), IIT Roorkee, Nov. 10-13, 2022. 40. N. K. Nishchal, “Opto-electronic asymmetric cryptosystem,” Int’l. Confer. on Electronic Materials and Applications (ICEMA-2022), Sept. 16-17, 2022, A. N. College, Patna [Invited]. 41. R. Kumar, N. K. Nishchal, and A. AlFalou, “Pattern identification using MACH filter through optical correlation,” Int’l. Confer. on Electronic Materials and Applications (ICEMA-2022), Sept. 16-17, 2022, A. N. College, Patna. 42. A. Shikder and N. K. Nishchal, “Optical vortex lattice generation through in-line phase modulation,” Int’l. Confer. on Electronic Materials and Applications (ICEMA-2022), Sept. 16-17, 2022, A. N. College, Patna. 43. N. K. Nishchal, “Structured light for information security,” Int’l. Confer. on Defence Research, Innovation and Technology (ICDRIT-2022), Sept. 15-16, 2022, Gujarat University, Ahmedabad, Souvenir, pp. 10-13 (2022). 44. A. Shikder and N. K. Nishchal, “Computer generated hologram encryption using array of vortex beams,” OPTICA Digital Holography and Three-Dimensional Imaging (DH-2022), Aug. 01-04, 2022, Robinson College, Cambridge University, Cambridge, UK. 45. A. Shikder, N. K. Nishchal, and P. Kumar, “Production of structured light beams through in-line wavefront shaping using spatial light modulator,” OPTICA Digital Holography and Three-Dimensional Imaging (DH-2022), Aug. 01-04, 2022, Robinson College, Cambridge University, Cambridge, UK. 46. P. Kumar, N. K. Nishchal, T. Omatsu, and A. S. Rao, “A compact optical set-up to create non-uniformly polarized high-order structured light beams,” Confer. on Lasers and Electro-optics, PacificRim 2022, (CLEO-PR 2022, ISOM’22, ODF’22), Sapporo, JAPAN, July 31-Aug. 06, 2022. 47. P. Kumar, N. K. Nishchal, T. Omatsu, and A. S. Rao, “Optimization of spatial light modulator’s phase response through computer-generated hologram,” OPTICA-Imaging and Applied Optics Congress, Vancouver, British Columbia, CANADA, July 11-15, 2022. 48. N. K. Nishchal, “Optical techniques for information security,” 2nd Int’l. Scientific Confer. (Hybrid) on Lasers, Optics. Photonics and Sensors (LOPS-2022), June 10-12, 2022, Fort Lauderdale, FL, USA [Invited]. 49. N. K. Nishchal, “Vector beam for information encoding,” Golden Jubilee Year Int’l. Confer. on Artificial Intelligence, Photonics, and Revolutionary Smart Materials (AIPRSM-2021), Oct. 25-26, 2021, L. N. Mithila Univ., Darbhanga [Invited]. 50. N. K. Nishchal, “Optical cryptography,” 2nd Edition – Laser, Optics, and Photonics Virtual (V-Optics-2021), Oct. 16-17, 2021 [Keynote Talk]. 51. A. K. Gupta and N. K. Nishchal, “Transport of intensity equation for low-light quantitative phase imaging and security applications,” Holography, Diffractive Optics, and Applications; SPIE/COS Photonics Asia 2021 (PA21), Oct. 10-12, 2021, Jiangsu, CHINA [Invited], Proc. SPIE 11898 (2021) 118980W. 52. N. K. Nishchal, “Image encryption using vector beam,” 2nd Int’l. Confer. on Digital Singular Optics: Applications and Fundamentals (DSO-2021), Sept. 06-10, 2021, Yalta, RUSSIA [Invited]. 53. P. Kumar and N. K. Nishchal, “Vector field encoding approach to secure color image,” OSA Imaging and Applied Optics Congress: Digital Holography and Three-Dimensional Imaging (DH-2021), July 19-23, 2021 (Online). 54. A. K. Gupta and N. K. Nishchal, “Composite method of transport of intensity equation for spatial frequency recovery,” OSA Imaging and Applied Optics Congress: Digital Holography and Three-Dimensional Imaging (DH-2021), July 19-23, 2021 (Online). 55. P. Kumar and N. K. Nishchal, “Creation and detection of singular light beams,” Student Conference on Photonics and Quantum Technology (CPQT-2021), Feb. 24-26, 2021, NISER Bhubaneswar (Online) [Invited]. 56. P. Kumar and N. K. Nishchal, “Generation of singular beams using electrically addressed spatial light modulator,” 5th Int’l. Confer. on Emerging Electronics, Nov. 26-28, 2020 (Online), IIT Delhi. 57. N. K. Nishchal, “A practical optical cryptosystem with partially coherent illumination,” Online Summit on Optics and Photonics (COP-2020), Nov. 26-27, 2020, Lisbon, PORTUGAL [Invited]. 58. P. Kumar and N. K. Nishchal, “Optical singularities in tailored light fields,” OSA Siegman International School on Lasers, July 20-24, 2020 (Online), Warsaw, POLAND. 59. P. Kumar and N. K. Nishchal, “Self-referenced interferometric methods to determine topological charge of vortex beams,” OSA Topical Meeting on Digital Holography and 3D Imaging (DH-2020), June 22-26, 2020 (Online). 60. P. Kumar and N. K. Nishchal, “Cylindrical vector beams by tailoring single polarization component,” OSA Topical Meeting on Digital Holography and 3D Imaging (DH-2020), June 22-26, 2020 (Online). 61. A. K. Gupta, P. Kumar, and N. K. Nishchal, “Fully-phase encryption using transport of intensity equation,” OSA Topical Meeting on Digital Holography and 3D Imaging (DH-2020), June 22-26, 2020 (Online). 62. A. K. Gupta, P. Kumar, and N. K. Nishchal, “Transport of intensity equation-based image encryption,” Int’l. OSA Network of Students Conference 2020 (IONS-2020), Feb. 29-March 02, 2020, IIT Delhi. 63. A. Kumar, R. K. Jha, and N. K. Nishchal, “Chromaticity weighted regularization technique for image dehazing,” Int’l. OSA Network of Students Conference 2020 (IONS-2020), Feb. 29-March 02, 2020, IIT Delhi. 64. P. Kumar and N. K. Nishchal, “Topological charge estimation of vortex beams through conjoined fork-like fringe pattern,” Int’l. OSA Network of Students Conference 2020 (IONS-2020), Feb. 29-March 02, 2020, IIT Delhi. 65. P. Kumar and N. K. Nishchal, “Determining orbital angular momentum of light by analyzing interferogram with conjoined fork-like structures,” Workshop on Recent Advances in Photonics (WRAP-2019), Dec. 13-14, 2019, IIT Guwahati. 66. A. K. Gupta and N. K. Nishchal, “Transport of intensity equation for phase imaging,” 20th Int’l. Symp. on Optomechatronic Technologies (ISOT-2019), Nov. 11-13, 2019, Goa [Invited]. 67. P. Kumar and N. K. Nishchal, “Self-referenced interferogram of Laguerre-Gaussian beams for topological charge determination,” 20th Int’l. Symp. on Optomechatronic Technologies (ISOT-2019), Nov. 11-13, 2019, Goa. 68. P. Kumar, A. Kumar, and N. K. Nishchal, “LED-based implementation of exclusive-OR operation for securing QR code,” Int’l. Confer. on Optics and Electro-optics (XLIII Symp. of Optical Society of India) (ICOL-2019), Oct. 19-22, 2019, IRDE Dehradun [Invited]. 69. A. Fatima and N. K. Nishchal, “Denoising imaging polarimetry by total variation reduction,” Int’l. Confer. on Optics and Electro-optics (XLIII Symp. of Optical Society of India) (ICOL-2019), Oct. 19-22, 2019, IRDE Dehradun. 70. A. Kumar, R. K. Jha, and N. K. Nishchal, “A weighted multi-scale fusion technique for single image haze removal,” Int’l. Confer. on Optics and Electro-optics (XLIII Symp. of Optical Society of India) (ICOL-2019), Oct. 19-22, 2019, IRDE Dehradun. 71. P. Kumar and N. K. Nishchal, “Self-referenced interferometric technique for determining high-order topological charges of vortex beams,” Int’l. Confer. on Optics and Electro-optics (XLIII Symp. of Optical Society of India) (ICOL-2019), Oct. 19-22, 2019, IRDE Dehradun. 72. A. K. Gupta and N. K. Nishchal, “Transport of intensity based photon counting phase imaging for non-invasive applications,” Int’l. Confer. on Optics and Electro-optics (XLIII Symp. of Optical Society of India) (ICOL-2019), Oct. 19-22, 2019, IRDE Dehradun. 73. A. K. Gupta and N. K. Nishchal, “Single shot transport of intensity equation based phase imaging using refractive index variation,” M5B.4, OSA Topical Meeting on Digital Holography and 3D Imaging (DH-2019), May 19-23, 2019, Bordeaux, FRANCE. 74. A. K. Gupta, A. Fatima, and N. K. Nishchal, “Phase imaging based on transport of intensity equation using liquid crystal variable waveplate,” M5B.7, OSA Topical Meeting on Digital Holography and 3D Imaging (DH-2019), May 19-23, 2019, Bordeaux, FRANCE. 75. P. Kumar and N. K. Nishchal, “Optical cryptosystems with quick response code,” Information Photonics-2019 (IP-19), April 24-26, 2019, Yokohama, JAPAN [Invited]. 76. N. K. Nishchal, “Securing information through light,” Int’l. Confer. on Photonics, Metamaterials, and Plasmonics (PMP-2019), Feb. 14-16, 2019, JIIT Noida [Invited]. 77. P. Kumar, A. Fatima, and N. K. Nishchal, “Multiple image security scheme based on Stokes parameter of spatially varying polarized beam,” The Int’l. Confer. on Fiber Optics and Photonics (PHOTONICS-2018), Dec. 12-15, 2018, IIT Delhi. 78. A. K. Gupta and N. K. Nishchal, “A non-interferometric phase retrieval using liquid crystal spatial light modulator,” The Int’l. Confer. on Fiber Optics and Photonics (PHOTONICS-2018), Dec. 12-15, 2018, IIT Delhi. 79. A. Kumar and N. K. Nishchal, “A multispectral image fusion technique based on single level integer wavelet transform,” The Int’l. Confer. on Fiber Optics and Photonics (PHOTONICS-2018), Dec. 12-15, 2018, IIT Delhi. 80. Yatish, A. Fatima, and N. K. Nishchal, “Two-stage optical hierarchical authentication based on interference with sparse phase information,” The Int’l. Confer. on Fiber Optics and Photonics (PHOTONICS-2018), Dec. 12-15, 2018, IIT Delhi. 81. A. Fatima and N. K. Nishchal, “Image encryption by phase and polarization modulation of light,” 7th Bihar Science Conference, An Int’l. Confer. on Science & Technology (BSC-2018), Dec. 04-06, 2018, College of Commerce, Arts, and Science, Patna. 82. N. K. Nishchal, “Vector beam with required phase-only functions for asymmetric image encryption,” XLII Annual Meeting of the Optical Society of India-Int’l. Symp. on Optics (OSI-ISO-2018), Sept. 19-22, 2018, IIT Kanpur [Invited]. 83. P. Kumar and N. K. Nishchal, “Generation of optical angular momentum of light using liquid crystal spatial light modulator,” XLII Annual Meeting of the Optical Society of India-Int’l. Symp. on Optics (OSI-ISO-2018), Sept. 19-22, 2018, IIT Kanpur. 84. A. K. Gupta and N. K. Nishchal, “Phase retrieval with liquid crystal variable retarder based on reference-less non-interferometric technique,” XLII Annual Meeting of the Optical Society of India-Int’l. Symp. on Optics (OSI-ISO-2018), Sept. 19-22, 2018, IIT Kanpur. 85. A. Fatima and N. K. Nishchal, “Simultaneous authentication verification of multiple secured images using joint transform correlation approach,” SPIE Security + Defence, Electro-optical and Infrared Systems: Technology and Applications, Sept. 10-13, 2018, Berlin, GERMANY. 86. N. K. Nishchal, “Optical asymmetric encryption schemes and attack analysis,” SPIE Security + Defence, Electro-optical and Infrared Systems: Technology and Applications, Sept. 10-13, 2018, Berlin, GERMANY. 87. A. Fatima, N. K. Nishchal, Y. Queo, A. Alfalou, and C. Brosseau, “Polarization-based encoding for optical cryptosystems,” 2nd Joensuu Confer. on Coherence & Random Polarization; Trends in Electromagnetic Coherence (COHERENCE-2018), June 12-15, 2018, Joensuu, FINLAND. 88. A. Fatima, N. K. Nishchal, A. Alfalou, and C. Brosseau, “Securing image authentication using a vector beam analysis,” 2nd Joensuu Confer. on Coherence & Random Polarization; Trends in Electromagnetic Coherence (COHERENCE-2018), June 12-15, 2018, Joensuu, FINLAND. 89. R. Shekhar, G. Unnikrishnan, and N. K. Nishchal, “Reconstruction quality improvement of digital holograms using multi-scale globa search,” JW4A.8 Digital Holography and 3D Imaging (Topical meeting), OSA Imaging and Applied Optics Congress, June 25-28, 2018, Orlando, Florida, USA. 90. R. Shekhar, G. Unnikrishnan, and N. K. Nishchal, “Multiplexing multiple digital holograms for efficient transmission and recovery,” JM4A.33 Digital Holography and 3D Imaging (Topical meeting), OSA Imaging and Applied Optics Congress, June 25-28, 2018, Orlando, Florida, USA. 91. A. K. Gupta and N. K. Nishchal, “Phase characterization of a liquid crystal spatial light modulator,” 3rd Int’l. Confer. on Microwave and Photonics (ICMAP-2018), Feb. 09-11, 2018, IIT (ISM) Dhanbad, pp. 37. 92. A. Kumar and N. K. Nishchal, “An image encryption scheme using quick response code,” 3rd Int’l. Confer. on Microwave and Photonics (ICMAP-2018), Feb. 09-11, 2018, IIT (ISM) Dhanbad, pp. 48. 93. N. K. Nishchal, “Optical security,” Workshop on Recent Advances in Photonics (WRAP-2017), Dec. 18-19, 2017, Mahindra Ecole Centrale, Hyderabad [Invited]. 94. A. Kumar and N. K. Nishchal, “A noise induced cryptographic hash function based on double random gyrator domain phase encoding,” Int’l. Confer. on Advances in Optics & Photonics (ICAOP-2017), Nov. 23-26, 2017, Hisar. 95. A. Fatima and N. K. Nishchal, “Information security through polarization encoding,” Int’l. Confer. on Advances in Optics & Photonics (ICAOP-2017), Nov. 23-26, 2017, Hisar [Invited]. 96. A. Fatima and N. K. Nishchal, “Phase modulation based optical asymmetric image encryption,” OSA Frontiers in Optics + Laser Science APS/DLS (FiO+LS 2017), Sept. 17-21, 2017, Washington, USA. 97. T. Pitkaaho, V. Pitkakangas, M. Niemela, S. K. Rajput, N. K. Nishchal, and T. J. Naughton, “Digital holographic sensor network and image analyses for distributed potable water monitoring,” Irish Machine Vision and Image Processing Conference (IMVIP-2017), Aug. 30-Sept. 01, 2017, Maynooth Univ., IRELAND. 98. N. K. Nishchal, “Optical encryption schemes,” UEM Congress 2017, Disruptive Technology & Disruptive Innovation – A Renaissance in this Century, Aug. 16-18, 2017, Sasin Graduate Institute of Business Administration, Cholalongkorn University, Bangkok, THAILAND [Invited]. 99. A. Kumar and N. K. Nishchal, “Quick response code-based asymmetric image encryption scheme,” Int’l. Topical Meeting on Applied and Adaptive Optics (INTOPMAA-17), Aug. 11-13, 2017, IIST Trivandrum. 100. Yatish, A. Fatima and N. K. Nishchal, “Multiple image encryption using unity modulus decomposition,” Int’l. Topical Meeting on Applied and Adaptive Optics (INTOPMAA-17), Aug. 11-13, 2017, IIST Trivandrum. 101. A. Fatima and N. K. Nishchal, “Asymmetric optical encryption schemes,” Int’l. Topical Meeting on Applied and Adaptive Optics (INTOPMAA-17), Aug. 11-13, 2017, IIST Trivandrum [Invited]. 102. T. Pitkaaho, V. Pitkakangas, M. Niemela, S. K. Rajput, N. K. Nishchal, and T. J. Naughton, “Digital holographic microscopy in remote potable water monitoring,” The Digital Holography and 3D Imaging (Topical meeting), May 29-June 01, 2017, Cheju Halla University, Jeju Island, SOUTH KOREA. 103. N. K. Nishchal, “Securing 3D information using digital holography,” The Digital Holography and 3D Imaging (Topical meeting), Th1A.2. May 29-June 01, 2017, Cheju Halla University, Jeju Island, SOUTH KOREA [Invited]. 104. A. Fatima and N. K. Nishchal, “Image encryption using Hartley transform domain polarization encoding,” The Int’l. Confer. on Fiber Optics and Photonics (PHOTONICS-2016), Dec. 04-08, 2016, IIT Kanpur. 105. N. K. Nishchal, “Securing digital holograms through watermarking,” The Int’l. Confer. on Fiber Optics and Photonics (PHOTONICS-2016), Dec. 04-08, 2016, IIT Kanpur. 106. Yatish, A. Fatima and N. K. Nishchal, “Barcode-based watermarking and optical encryption,” The Int’l. Confer. on Fiber Optics and Photonics (PHOTONICS-2016), Dec. 04-08, 2016, IIT Kanpur. 107. A. Fatima and N. K. Nishchal, “Asymmetric optical cryptosystem; Attack analysis,” Int’l. Confer. on Light and Light-based Technologies (ICLLT-2016), Nov. 26-28, 2016, Tezpur Univ. 108. D. Kumar and N. K. Nishchal, “Digital holography for recognition and information security of 3D objects,” 3rd Int’l. Confer. on Opto-elctronics & Applied Optics (OPTRONIX-2016), Aug. 18-20, 2016, Univ. of Engineering & Management, Kolkata [Invited]. 109. A. Fatima and N. K. Nishchal, “Single public key dependent attack on optical asymmetric cryptosystem,” 3rd Int’l. Confer. on Opto-elctronics & Applied Optics (OPTRONIX-2016), Aug. 18-20, 2016, Univ. of Engineering & Management, Kolkata. 110. N. K. Nishchal, “Optical security for future era,” IEEE 5G Summit, March 29-31, 2016, IIT Patna. 111. N. K. Nishchal, “Optical asymmetric cryptosystem and cryptanalysis,” Int’l. Confer. on Opto-Electronics and Applied Optics, (IEEE IEM OPTRONIX-2015) Oct. 16-17, 2015, Univ. of British Columbia, Vancouver, CANADA [Invited]. 112. D. Kumar and N. K. Nishchal, “Three-dimensional object recognition using phase-only computer-generated Fresnel hologram,” Int’l. Confer. on Opto-Electronics and Applied Optics, (IEEE IEM OPTRONIX-2015) Oct. 16-17, 2015, Univ. of British Columbia, Vancouver, CANADA. 113. I. Mehra and N. K. Nishchal, “Optical asymmetric cryptosystem and wavelet based image fusion,” Int’l. Symp. on 3D Imaging, Metrology, Data Security (3DIM-DS 2015), Sept. 26-29, 2015, Shenzen, CHINA [Invited]. 114. D. Kumar and N. K. Nishchal, “Phase-only computer generated Fresnel hologram synthesis using a symmetrical three-dimensional GS algorithm,” Siegman International School on Lasers: 2015, Aug. 02-07, 2015, Amberg, GERMANY. 115. D. Kumar and N. K. Nishchal, “Digital holography based 3D object recognition under varying light illumination using photon counting imaging,” Int’l. Confer. on Digital Holography & 3-D Imaging, May 24-28, 2015, Shanghai Institute of Optics and Fine Mechanics, Shanghai, CHINA. 116. I. Mehra and N. K. Nishchal, “Double image encryption using gyrator wavelet transform,” Int’l. Confer. on Optics & Photonics (ICOP-2015), Feb. 20-22, 2015, Univ. of Calcutta. 117. D. Kumar, S. K. Rajput, and N. K. Nishchal, “Hologram watermarking with color image via phase multiplexing and photon counting imaging technique,” Int’l. Confer. on Optics & Photonics (ICOP-2015), Feb. 20-22, 2015, University of Calcutta. 118. D. Kumar and N. K. Nishchal, “Digital holography for three-dimensional object recognition,” 6th Bihar Science Conference; An Int’l. Confer. on Science & Technology, Dec. 23-25, 2014, Magadh Mahila College, Patna. 119. D. Kumar and N. K. Nishchal, “Performance enhancement of joint fractional correlator for digital holography based three-dimensional object recognition using wavelet filter,” Int’l. Confer. on Opto-electronics and Applied Optics (IEM-OPTRONIX-2014), Dec. 17-18, 2014, IEM Kolkata. 120. I. Mehra and N. K. Nishchal, “Pan-sharpened image optical encryption,” Int’l. Confer. on Opto-electronics and Applied Optics (IEM-OPTRONIX-2014), Dec. 17-18, 2014, IEM Kolkata. 121. S. K. Rajput and N. K. Nishchal, “Simultaneous encryption of gray-scale and color images,” 12th Int’l. Confer. on Fiber Optics and Photonics (PHOTONICS’14), Dec. 13-16, 2014, IIT Kharagpur. 122. D. Kumar and N. K. Nishchal, “Digital holography based three-dimensional object recognition using binary differential joint transform correlator,” 12th Int’l. Confer. on Fiber Optics and Photonics (PHOTONICS’14), Dec. 13-16, 2014, IIT Kharagpur. 123. A. Fatima, I. Mehra, and N. K. Nishchal, “Plasmonics-based keys for optical image encryption,” 12th Int’l. Confer. on Fiber Optics and Photonics (PHOTONICS’14), Dec. 13-16, 2014, IIT Kharagpur. 124. I. Mehra and N. K. Nishchal, “Optical asymmetric cryptosystem based on axial translation of image sensor,” 12th Int’l. Confer. on Fiber Optics and Photonics (PHOTONICS’14), Dec. 13-16, 2014, IIT Kharagpur. 125. A. Fatima, I. Mehra, D. Kumar, and N. K. Nishchal, “Plasmonics based keys for image encryption that uses exclusive OR logic operation,” COMSOL Conference 2014, Bangalore, Nov. 13-14, 2014. 126. N. K. Nishchal, “3D optical information security,” Collaborative Conference on 3D & Materials Research (CC3DRM-2014), June 23-27, 2014, Incheon, Seoul, SOUTH KOREA [Invited]. 127. D. Kumar and N. K. Nishchal, “Identification of three-dimensional objects using nonlinear joint fractional Fourier transform correlator,” XVI Annual Confer. of Int’l. Academy of Physical Sciences on Physical Sciences and Technology for Sustainable Development (CONIAPS’14), March 20-22, 2014, IIITDM Jabalpur. 128. D. Kumar and N. K. Nishchal, “Identification of three-dimensional objects using nonconventional joint fractional Fourier transform correlator,” Int’l. Confer. on Optics & Optoelectronics (ICOL’14), March 05-08, 2014, Dehradun. 129. N. K. Nishchal and S. K. Rajput, “Optical asymmetric cryptosystem,” Int’l. Confer. on Optics & Optoelectronics (ICOL’14), March 05-08, 2014, Dehradun. 130. I. Mehra and N. K. Nishchal, “Securing image using interference and diffractive imaging,” Int’l. Confer. on Optics & Optoelectronics (ICOL’14), March 05-08, 2014, Dehradun. 131. S. K. Rajput and N. K. Nishchal, “Optical decryption of asymmetric cryptosystem based on phase-truncated Fourier transform,” Int’l. Confer. on Optics & Optoelectronics (ICOL’14), March 05-08, 2014, Dehradun. 132. I. Mehra and N. K. Nishchal, “Multiple image hiding based on joint transform correlator and modified Gerchberg-Saxton phase retrieval algorithm” Int’l. Confer. on Optics-photonics Design & Fabrication, 13PSb-04, 287-288, Feb. 12-14, 2014, Tokyo, JAPAN. 133. I. Mehra and N. K. Nishchal, “A novel asymmetric cryptosystem for securing multiple images,” Int’l. Confer. on Optics-photonics Design & Fabrication, 13PSb-05, 289-290, Feb. 12-14, 2014, Tokyo, JAPAN. 134. N. K. Nishchal, “Digital holographic microscopy,” Int’l. Confer. on Role of Science and Technology in Progress of World,” Desidoc, DRDO, Dec. 05-07, 2013. 135. S. K. Rajput and N. K. Nishchal, “Optical asymmetric cryptosystem using polarized light,” Int’l. Confer. on 2013 Optical Engineering + Applications in SPIE Optics + Photonics, Aug. 25-29, 2013, San Diego, USA. Proc. SPIE 8855 (2013) 885503. 136. S. K. Rajput and N. K. Nishchal, “Known-plaintext attack on asymmetric cryptosystem,” Int’l. Confer. on 2013 Optical Engineering + Applications in SPIE Optics + Photonics, Aug. 25-29, 2013, San Diego, USA. Proc. SPIE 8855 (2013) 88550U. 137. S. K. Rajput and N. K. Nishchal, “Multiple image encryption based on known-plaintext attack and modified G-S phase retrieval algorithm,” International Conference on Optics in Precision Engineering and Nanotechnology (icOPEN 2013) April 9-11, 2013, Singapore Expo, SINGAPORE, Proc. SPIE 8769 (2013) 87690X. 138. S. K. Rajput and N. K. Nishchal, “Fractional domain asymmetric cryptosystem and cryptanalysis,” International Conference on Optics in Precision Engineering and Nanotechnology (icOPEN 2013) April 9-11, 2013, Singapore Expo, SINGAPORE, Proc. SPIE 8769 (2013) 87691Y [Invited paper]. 139. I. Mehra, S. K. Rajput, and N. K. Nishchal, “Collision in phase truncation based asymmetric cryptosystem in Fresnel domain,” Eleventh Int’l. Confer. on Fiber Optics and Photonics (PHOTONICS’12), IIT Madras, Dec. 09-12, 2012. 140. S. K. Rajput, Himanshu, and N. K. Nishchal, “Color image encryption using polarized light,” Eleventh Int’l. Confer. on Fiber Optics and Photonics (PHOTONICS’12), IIT Madras, Dec. 09-12, 2012. 141. N. K. Nishchal, T. Pitkaaho, S. Krishnan, and A. Maninnen, “Real-time three-dimensional visualization of Escherichia coli using digital holographic microscope,” Eleventh Int’l. Confer. on Fiber Optics and Photonics (PHOTONICS’12), IIT Madras, Dec. 09-12, 2012. 142. S. K. Rajput and N. K. Nishchal, “Image encryption based on phase-truncation and interference using fractional Fourier transform,” First International OSA Network of Students (IONS) Conference, IIT Delhi, Dec. 01-02, 2011. 143. S. K. Rajput and N. K. Nishchal, “Joint fractional Fourier transform correlator for encrypted image verification,” Photonics Ireland 2011, Sept. 07-09, 2011, Dublin, IRELAND. 144. N. K. Nishchal, “Effect of image processing operations on fractional Fourier transform based image watermarking technique,” Photonics Ireland 2011, Sept. 07-09, 2011, Dublin, IRELAND. 145. N. K. Nishchal and T. J. Naughton, “Reconstruction of Fresnel digital hologram using fractional Fourier transform algorithm,” Tenth Int’l. Confer. on Fiber Optics and Photonics (PHOTONICS’10), IIT Guwahati, Dec. 11-15, 2010. 146. M. R. Ansari and N. K. Nishchal, “Securing watermarked information using fractional Fourier transform,” Tenth Int’l. Confer. on Fiber Optics and Photonics (PHOTONICS’10), IIT Guwahati, Dec. 11-15, 2010. 147. N. K. Nishchal, “Fractional Fourier domain optical image watermarking,” Proc. of 16th Microoptics Conference (2010 MOC), pp. 84-85, Oct. 31-Nov. 3, 2010, Hsinchu, TAIWAN. 148. N. K. Nishchal, “Wavelet-based distortion-invariant correlation filters; A review,” Proc. of 16th Microoptics Conference (2010 MOC), pp. 326-327, Oct. 31-Nov. 3, 2010, Hsinchu, TAIWAN. 149. N. K. Nishchal, T. Pitkaaho, and T. J. Naughton, “Digital Fresnel hologram watermarking,” Proc. of 9th Euro-American Workshop on Information Optics (WIO 2010), July 11-16, 2010, Helsinki, FINLAND. cc.oulu.fi/~tpitaa/varasto/05582496.pdf 150. N. K. Nishchal and T. J. Naughton, “Three-dimensional image watermarking using fractional Fourier transform,” Proc. of Int’l Confer. on Optics and Photonics (ICOP-2009), CSIO Chandigarh, Oct. 30-Nov. 01, 2009. 151. N. K. Nishchal and T. J. Naughton, “Three-dimensional optical image encryption using fractional Fourier transform,” Ninth Int’l Confer. on Optoelectronics, Fiber Optics, and Photonics (PHOTONICS’08), IIT Delhi, Dec. 13-17, 2008. 152. A. Bhagatji, N. K. Nishchal, A. K. Gupta, and B. P. Tyagi, “Fringe-adjusted filter-based fractional joint transform correlator,“ Indo-Japan Workshop on Recent Developments in Optics and Photonics, IIT Delhi, Dec. 14, 2007, pp. 133-136. 153. V. K. Beri, S. Goyal, N. K. Nishchal, and A. K. Gupta, “Wavelet-modified maximum average correlation height filter for out-of-plane rotation invariance,” Eighth Int’l Confer. on Optoelectronics, Fiber Optics, and Photonics (PHOTONICS’06), Dec. 13-16, 2006, Hyderabad. 154. A. Aran, N. K. Nishchal, and V. K. Beri, “Log-polar transform based wavelet modified maximum average correlation height filter for rotation and scale invariant target recognition,” Eighth Int’l Confer. on Optoelectronics, Fiber Optics, and Photonics (PHOTONICS’06), Dec. 13-16, 2006, Hyderabad. 155. S. Goyal, N. K. Nishchal, and V. K. Beri, “Chirp-encoded MACH filter-based hybrid digital-optical correlator,” Int’l Confer. on Optics and Optoelectronics, IRDE Dehradun, Dec. 12-15, 2005. 156. A. Bhagatji, N. K. Nishchal, and V. K. Beri, “Influence of perturbations in a hybrid digital-optical correlator,” Int’l. Confer. on Optics and Optoelectronics, IRDE Dehradun, Dec. 12-15, 2005. 157. A. Kumar, N. K. Nishchal, and A. K. Gupta, “Genetic algorithm for composite wavelet-matched filter with application to out-of-plane rotated targets,” Int’l Confer. on Optics and Optoelectronics, IRDE Dehradun, Dec. 12-15, 2005. 158. K. Singh and N. K. Nishchal, “Applications of fractional Fourier transform in optical data security,” Proc. Int’l Confer. on Optoelectronic Technology, (Nirali Prakashan, Pune, 2004), Ed., D. K. Gautam, Jan. 12-14, 2004, North Maharashtra Univ., Jalgaon, pp. 244-266. 159. N. K. Nishchal, R. John, and K. Singh, “Optical data security and holographic storage,” Proc. Int’l Confer. on Laser Applications and Optical Metrology, Eds. C. Shakher and D. S. Mehta, (Anamaya Publs., New Delhi, 2004) Dec. 01-04, 2003, IIT Delhi, New Delhi, pp. 126-134. 160. N. K. Nishchal, J. Joseph, and K. Singh, “Data security using digital holography,” Proc. Int’l Confer. on Laser Applications and Optical Metrology, Eds. C. Shakher and D. S. Mehta, (Anamaya Publs., New Delhi, 2004) Dec. 01-04, 2003, IIT Delhi, New Delhi, pp. 563-567. 161. N. K. Nishchal, J. Joseph, and K. Singh, “Fully phase encryption using fractional Fourier transform,” Proc. Sixth Int’l Confer. on Optoelectronics, Fiber Optics, and Photonics (PHOTONICS’02), Dec. 16-18, 2002, TIFR Mumbai. 162. N. K. Nishchal and K. Singh, “Fractional Fourier transform techniques in optical data security,” Proc. Int’l Confer. on Opto-electronics and Laser Applications, Oct. 02-03, 2002, Jakarta, INDONESIA, pp. D04-D08. 163. N. K. Nishchal, J. Joseph, and K. Singh, “Optical phase encryption system that uses phase conjugation and phase contrast,” Proc. 3rd Int’l Confer. on Optics-Photonics Design & Fabrication (ODF’02), Oct. 30-Nov. 01, 2002, Tokyo, JAPAN, pp. 141-142. 164. N. K. Nishchal, J. Joseph, and K. Singh, “Phase contrast using electrically addressed liquid crystal spatial light modulator,” Proc. 3rd Int’l. Confer. on Optics-Photonics Design & Fabrication (ODF’02), Oct. 30-Nov. 01, 2002, Tokyo, JAPAN, pp. 109-110. 165. N. K. Nishchal, J. Joseph, and K. Singh, “A multichannel optical wavelet processor,” 2nd Int’l Confer. & 27th Annual Convention of Opt. Soc. India, Aug. 27-29, 2001, Trivandrum, India.
Invited Talks
    1. N. K. Nishchal, “Photorefractive optics,” Refresher Course on X-Ray Crystallography, and X-Ray Photoelectron Spectroscopy with Density Functional Theory Calculations, IIT (ISM) Dhanbad, Aug. 26, 2024.
    2. N. K. Nishchal, “Optical technology for information security,” One Day Seminar on Advances in Photonics, IIT Bhubaneswar, March 22, 2024.
    3. N. K. Nishchal, “Optical cryptography through structured light,” Department of Physics, Indian Institute of Space Science and Technology, Thiruvananthapuram, Feb. 15, 2024.
    4. N. K. Nishchal, “Optical cryptography through structured light,” Short Course on Emerging Materials and their Societal Impacts, NIT Patna, Nov. 06-10, 2023.
    5. N. K. Nishchal, “Securing information with structured light,” Department of Physics, Sikkim University, Gangtok, May 24, 2023.
    6. N. K. Nishchal, “Interference in thin films and digital holographic microscopy,” DST-STUTI sponsored hands-on training program on Training for Developing Skills on Research Equipment in Physics and Biotechnology, Central University of South Bihar, Gaya, Jan. 21, 2023.
    7. N. K. Nishchal, “Interference and diffraction of light,” REvitalizing School Physics Education through Concept-oriented Teaching in Bihar for PGTs, IIT Patna, Jan. 18, 2023.
    8. N. K. Nishchal, “Understanding physics: Classes IX-X,” Instructional School for Mathematical Foundation for Classes XI-XII, Dept. of Mathematics, IIT Patna, Oct. 16, 2022.
    9. N. K. Nishchal, “Understanding wave optics,” Instructional School for Mathematical Foundation for Classes XI-XII, Dept. of Mathematics, IIT Patna, Oct. 10, 2022.
    10. N. K. Nishchal, “Digital holographic microscope,” Workshop on High-end Equipments: Fabrication & Characterization of Electronic Devices, SERB-IIT Patna, July 26, 2022.
    11. N. K. Nishchal, “Optical encryption,” Summer School on Optics and Photonics, Optics and Photonics Centre, IIT Delhi, June 14, 2022.
    12. N. K. Nishchal, “Optics and photonics for the benefit of society,” Popular lecture during ‘Vigyan Sarvatra Pujyate’, Shrikrishna Science Centre, Patna, Feb. 28, 2022.
    13. N. K. Nishchal, “Light in energy conservation,” National Energy Conservation Day, The Institution of Engineers, Bihar State Centre, Patna, Dec. 14, 2021.
    14. N. K. Nishchal, “Photonics technology,” World Standards Day, Bureau of Indian Standards, Patna, Oct. 29, 2021.
    15. N. K. Nishchal, “Photorefractive optics,” Faculty Development Programme on Novel Materials under AICTE Training and Learning (ATAL) Academy, A. N. College, Patna, Aug. 27, 2021.
    16. N. K. Nishchal, “Photonics for society,” Webinar, Bhagalpur College of Engineering, Bhagalpur, Sept. 18, 2020.
    17. N. K. Nishchal, “Photonics in the digital era; UV light killer of Corona virus,” Webinar, Bakhtiyarpur College of Engineering, Bakhtiyarpur, Aug. 09, 2020. https://www.youtube.com/watch?v=QTK-4gq0vDg
    18. N. K. Nishchal, “Light as a tool for development,” Webinar, Gaya Engineering College, Gaya, Aug. 06, 2020.
    19. N. K. Nishchal, “Light for information encoding,” Department of Physics, Indian Institute of Technology (Banaras Hindu University), Varanasi, May 10, 2019.
    20. N. K. Nishchal, “Vector beam based asymmetric image encryption,” Faculty of Systems Engineering, Wakayama University, Wakayama, JAPAN, April 23, 2019.
    21. N. K. Nishchal, “Light for information security,” Department of Applied Optics and Photonics, University of Calcutta, Kolkata, April 01, 2019.
    22. N. K. Nishchal, “Vector beam with required phase-only functions for image encryption,” Centre for Nonlinear Science, Westfalische Wilhelms-Universitat, Muenster, GERMANY, Sept. 14, 2018.
    23. N. K. Nishchal, “Physical optics and holography,” Workshop at Delhi Public School, Patna, August 18, 2018.
    24. N. K. Nishchal, “Light for information encoding,” REvitalizing School Physics Education through Concept-oriented Teaching in KVs (RESPECT KVs) for PGTs, IIT Patna, August 07, 2018.
    25. N. K. Nishchal, “Tools and techniques of space exploration,” On the occasion of Moon Landing Day at Srikrishna Vigyan Kendra, Patna, July 20, 2018.
    26. N. K. Nishchal, “Holography and its applications,” REvitalizing School Physics Education through Concept-oriented Teaching in KVs (RESPECT KVs) for PGTs, IIT Patna, July 18, 2018.
    27. N. K. Nishchal, “Optics for information security,” Refresher Programme in Physics, Faculty Development Centre, IIT (ISM) Dhanbad, June 13, 2018.
    28. N. K. Nishchal, “Information optics,” Refresher Programme in Physics, Faculty Development Centre, IIT (ISM) Dhanbad, June 12, 2018.
    29. N. K. Nishchal, “Diffraction and Interference,” REvitalizing School Physics Education through Concept-oriented Teaching in KVs (RESPECT KVs) for PGTs, IIT Patna, April 07-09, 2017.
    30. N. K. Nishchal, “Basics of wave optics,” REvitalizing School Physics Education through Concept-oriented Teaching in KVs (RESPECT KVs) for PGTs, IIT Patna, Oct. 21, 2016.
    31. N. K. Nishchal, “Techniques of optical information security,” Special Lecture to M. Phil. Students, Department of Physics, B. R. A. Bihar University, Muzaffarpur, Sept. 20, 2015.
    32. N. K. Nishchal, “Digital holography and image encryption techniques,” 15th Refresher Course, University Department of Physics, B. R. A. Bihar University, Muzaffarpur, Feb. 04, 2015.
    33. N. K. Nishchal, “Basics of optics: interference, diffraction, and polarization,” 15th Refresher Course, University Department of Physics, B. R. A. Bihar University, Muzaffarpur, Feb. 03, 2015.
    34. N. K. Nishchal, “Optical techniques of image encryption, watermarking, and 3D target identification,” 3D Display Research Centre, Department of Electronics Engineering, Kwangwoon University, Seoul, SOUTH KOREA, June 28, 2014.
    35. N. K. Nishchal, “Digital holography and its applications,” Seminar on Laser and its Applications, University Department of Physics, B. R. A. Bihar University, Muzaffarpur, March 31, 2014.
    36. N. K. Nishchal, “Understanding fiber-optic communication,” Inservice Course of PGT (Physics) Kendriya Vidyalaya Sangathan, Kendriya Vidyalaya, Bailey Road, Patna, Dec. 24, 2013.
    37. N. K. Nishchal, “Interference and diffraction of light,” Bihar INSPIRE Internship Science Camp, Jagdam College Chapra, Oct. 31, 2013.
    38. N. K. Nishchal, “Optical watermarking techniques,” Room No. 321, Department of Physics, Capital Normal University, Beijing, CHINA, June 24, 2013.
    39. N. K. Nishchal, “Optical image encryption techniques,” Room No. 321, Department of Physics, Capital Normal University, Beijing, CHINA, June 20, 2013.
    40. N. K. Nishchal, “Wave optics,” Inservice Course of PGT (Physics) Kendriya Vidyalaya Sangathan, Kendriya Vidyalaya, Bailey Road, Patna, May 22, 2013.
    41. N. K. Nishchal, “Lasers and its applications,” INSPIRE (Innovation in Science Pursuit for Inspired Research) Internship Science Camp, Pre-Examination Training Centre, Patna Univ., March 18, 2013.
    42. N. K. Nishchal, “Optical pattern recognition and information security,” One Day Workshop on Optical Signal and Image Processing Techniques, Jan. 19, 2013, VIT University, Chennai.
    43. N. K. Nishchal, “Microscopes,” Bihar INSPIRE Internship Science Camp, Jagdam College Chapra, Jan. 16, 2013.
    44. N. K. Nishchal, “Digital holography,” One Day Seminar on Development of Nano-Technology Sensors for Defence Applications: Nano-Scale Innovation, Vidyadaan Institute of Technology and Management, Dumraon, Buxar, Sept. 16, 2012.
    45. N. K. Nishchal, “Optical microscope,” INSPIRE (Innovation in Science Pursuit for Inspired Research) Internship Science Camp, Pre-Examination Training Centre, Patna Univ., Aug. 30, 2012.
    46. N. K. Nishchal, “Photonic correlator,” Bihar INSPIRE Internship Science Camp, Jagdam College Chapra, July 18, 2012.
    47. N. K. Nishchal, “Optical information processing,” Contact Programme for Talented +2 School Students, at the Mahavir Cancer Sansthan & Research Centre, Patna, April 26, 2012.
    48. N. K. Nishchal, “Holography and its applications,” INSPIRE (Innovation in Science Pursuit for Inspired Research) Internship Science Camp, Pre-Examination Training Centre, Patna University, Feb. 27, 2012.
    49. N. K. Nishchal, “Optoelectronic techniques of image encryption, watermarking, and target identification,” Department of Computer Science, National University of Ireland Maynooth, IRELAND, Sept. 12, 2011.
    50. N. K. Nishchal, “Optoelectronic techniques of information security,” Bihar INSPIRE Internship Science Camp, Jagdam College Chapra, Aug. 07, 2011.
    51. N. K. Nishchal, “Optoelectronic techniques of 3D information security,” at Industrial Technology Research Institute, Hsinchu, TAIWAN, Nov. 04, 2010.
    52. N. K. Nishchal, “Laser and its applications,” Motivation Programme for Talented School Students of +2, at the Mahavir Cancer Sansthan, Patna, Sept. 24, 2010.
    53. N. K. Nishchal, “Optical information processing using Matlab,” Short Term Training Programme on “Exposure on MATLAB,” at the National Institute of Technical Teachers’ Training & Research Extension Centre, Guwahati, March 13, 2008.

     
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