Raj Kumar

Scopus Publications

Polarization-based real-time diffraction efficiency measurement of reflection volume holographic gratings
Rajveer Kaur, Komal Sharma, Saikat Saha, Raj Kumar
Applied Optics, 2026
Holographic gratings play a crucial role in various applications, including spectroscopy, displays, security holograms, and sensing technologies. Real-time monitoring of the diffraction efficiency of these gratings is essential for improving fabrication processes and performance optimization. For many applications, such as displays and sensing, reflection volume holographic gratings (RVHGs) are preferred over transmission gratings due to their high wavelength selectivity. Existing real-time diffraction efficiency measurement setups typically rely on the Bragg degenerate method, which requires two lasers, resulting in increased cost and bulkiness. Also, it requires precise wavelength tuning and alignment, making the system more complex. Therefore, we propose a polarization-based novel, to the best of our knowledge, setup that performs real-time measurement of the diffraction efficiency of RVHGs with a single laser source. In this approach, the probe beam, having a different polarization state than the recording beams, provides real-time measurements, demonstrating a simplified method for the characterization and optimization of RVHGs. Furthermore, the refractive index modulation and polymerization rates are calculated for RVHGs recorded in photopolymer film, which are essential for determining grating quality and optical performance. Application of the proposed method is demonstrated in the optimization of holographic couplers required for the holographic waveguide-based near-eye augmented reality displays.
Holographically sensing of volatile organic compounds using cellulose acetate-based photopolymer film
Komal Sharma, Girish C Mohanta, Raj Kumar
Scientific Reports, 2025
Volatile organic compounds (VOCs) are recognized as significant environment pollutants, necessitating the development of rapid sensing methods characterized by ease of fabrication, low cost, and reusability. This demand is prevalent across various industries and laboratories. Several types of sensors, such as electrochemical sensors, semiconductor sensors, catalytic combustion sensors, and optical fiber-based sensors, have been reported for VOC detection. However, most of these sensors have a complex fabrication process and/or slow response time, which limits their applications. To overcome these limitations, the present work introduces a novel particle-free cellulose acetate-based photopolymer sensor film for the first time for VOC detection. The sensing performance of the film was evaluated by determining the diffraction efficiency of a holographically recorded transmission grating. A diffraction efficiency of 70% was achieved for the pristine film. Upon exposure to VOCs, the diffraction efficiency decreased by 29.52% for acetone, 12.09% for isopropyl alcohol (IPA), and 15.90% for tetrahydrofuran (THF) with a response time of 99 sec., 202 sec., and 170 sec., respectively. The sensor exhibited full recovery for multiple cycles. The proposed particle-free composition of the sensor film responds better than the nanoparticle-based sensor films.
Comparison of numerical reconstruction of digital holograms using angular spectrum method and Fresnel diffraction method
Gaurav Dwivedi, Anuj Sharma, Sanjit Debnath, Rajkumar
Journal of Optics India, 2025
Enhancing field of view of digital holography using an angular multiplexed holographic optical element
Lavlesh Pensia, Manoj Kumar, Osamu Matoba, Raj Kumar
Optics Letters, 2025
Digital holography (DH) is capable of the most precise multidimensional imaging and measurements in various fields ranging from optical metrology to biomedical imaging. However, DH has not progressed in accordance with its capabilities. The fundamental and technically challenging roadblock of DH is the small field of view (FOV) restricted by the parameters of the available digital image sensors. Here, we introduce a novel approach, to our knowledge, via the use of a specialized multiplexed holographic optical element that overcomes the limit of the maximum angle between the object and reference beams without violating the sampling theorem and achieves wide FOV, of more than 35°, in off-axis DH. The proof of the concept of the proposed wide FOV DH system is experimentally demonstrated by recording digital holograms of objects placed within the realm of an angular range of 0° to 35°. The method may be useful for various applications, including non-destructive testing, biomedical engineering, holographic displays, communication, entertainment, and beyond those envisioned in this paper.
Improved color uniformity in monochrome holographic waveguide based near eye displays
Rajveer Kaur, Bhargab Das, Jae-Hyeung Park, Raj Kumar
Optics Express, 2025
The use of near eye displays (NEDs) in applications such as head-mounted displays requires high color uniformity across a wide field of view (FOV). However, volume holographic gratings (VHGs), while suitable for NEDs, suffer from high angular selectivity, limiting the FOV for monochromatic light and causing color dispersion when illuminated by a broadband light source, leading to color variations across the displayed image. To address this issue, we report a method to simultaneously enhance the FOV and improve color uniformity by designing Bragg-matched, reflection-type, angular multiplexed VHGs. This approach ensures consistent diffraction properties for different angles of incidence, producing uniform color across the entire FOV. Numerical simulations demonstrate a reduction in spectral bandwidth from 42.7 nm to 14.7 nm throughout a 24o FOV, by using 3 times multiplexed holographic couplers. The experimentally measured FOV is approximately 25.3°. Further measurements performed using a spectroradiometer show that the multiplexed waveguide system exhibits improved color uniformity across the FOV compared to the conventional waveguide with red and blue contributions reduced from 47.8% to 0% and 20.6% to 8.5%, respectively. The optical simulations and experimental validation show a significant improvement in color uniformity compared to conventional methods, making it highly suitable for applications requiring precise and consistent color output.
Advances in Optical Metrology: High-Bandwidth Digital Holography for Transparent Objects Analysis
Manoj Kumar, Lavlesh Pensia, Karmjit Kaur, Raj Kumar, Yasuhiro Awatsuji, Osamu Matoba
Photonics, 2025
Accurate and non-invasive optical metrology of transparent objects is essential in several commercial and research applications, from fluid dynamics to biomedical imaging. In this work, a digital holography approach for thickness measurement of glass plate and temperature mapping of candle flame is presented that leverages a double-field-of-view (FOV) configuration combined with high spatial bandwidth utilization (SBU). By capturing a multiplexed hologram from two distinct objects in a single shot, the system overcomes the limitations inherent to single-view holography, enabling more comprehensive object information of thickness measurement and temperature-induced refractive index variations. The method integrates double-FOV digital holography with high SBU, allowing for accurate surface profiling and mapping of complex optical path length changes caused by temperature gradients. The technique exhibits strong potential for applications in the glass industry and microfluidic thermometry, convection analysis, and combustion diagnostics, where precise thermal field measurements are crucial. This study introduces an efficient holographic framework that advances the capabilities of non-contact measurement applications by integrating double-FOV acquisition into a single shot with enhanced spatial bandwidth exploitation. The approach sets the groundwork for real-time, volumetric thermal imaging and expands the applicability of digital holography in both research and industrial settings.
Lensless Fourier transform multiplexed digital holography
Manoj Kumar, Lavlesh Pensia, Raj Kumar, Osamu Matoba
Optics Letters, 2025
In this work, a new framework of lensless Fourier transform multiplexed digital holography (LFTMDH) is proposed, leveraging the double field of view (FoV) in a single-shot recording. The proof-of-concept system with double FoV is realized by adopting a spatially multiplexing technique by inserting a cube beam splitter in the object path. The cube beam splitter divides the object beam into two FoVs with different object information. By carefully aligning and optimizing the orientation of the cube beam splitter, these two FoVs along with a spherical reference beam (generated at the object plane) are allowed to interfere with the active region of an image sensor, resulting in a multiplexed Fourier digital hologram. The object information (amplitude and phase) is obtained by applying a single Fourier transform to the recorded digital hologram, making the technique faster with the added benefit of double FoV, compared to its counterparts. The feasibility and advantages of the proposed system are demonstrated through experimental validation and comparative analysis with the existing system. The results indicate that the proposed system not only achieves double FoV imaging in a single-shot recording but also maintains spatial resolution in the reconstructed images. Its applications span various fields, such as biological microscopy, nondestructive testing, and optical metrology, where wider FoV is crucial.
Prism-free fabrication of multiplexed holographic waveguide couplers for full-color near-eye displays
Rajveer Kaur, Raj Kumar
Journal of Information Display, 2025
Full-color holographic waveguide couplers are required in advanced augmented reality (AR) near-eye display (NED) technologies due to their superior light manipulation capabilities. However, the traditional fabrication process relies on prisms to fabricate the holographic grating structures, posing significant challenges for large-scale manufacturing. The present work addresses this issue by proposing a prism-free fabrication design for full-color waveguide couplers. Our technique utilizes wavelength shifting and multiplexing of volume holographic gratings (VHGs) with three sequential exposures on a single film. The theoretical analysis, validated by optical simulations, demonstrates flexibility in selecting propagation angles that successfully transmit the correct color spectra for each color-specific grating through the waveguide. The experimental verification, which involves the fabrication of multiplexed VHGs, demonstrates the capability of reproducing true colors, thereby making waveguides based on this technology suitable for full-color AR NEDs, which could meet the current requirements of commercial companies in healthcare, gaming, and manufacturing.
Vibration Measurement of 3-D Objects With Single-Shot Double Field-of-View High-Speed Digital Holography
Manoj Kumar, Lavlesh Pensia, Raj Kumar, Osamu Matoba
IEEE Transactions on Instrumentation and Measurement, 2025
Vibration measurement is critical in engineering as it plays a vital role in ensuring the safety, reliability, and performance of machinery, structures, and systems. Non-destructive techniques, such as digital holography for vibration measurements, are most important for assessing the dynamic behavior of structures and materials without inflicting damage or alteration with high resolution and precision. In this work, to the best of our knowledge, for the first time, we experimentally demonstrated a high-speed digital holography approach for out-of-plane displacement and vibration measurements of 3-D objects in a single-shot acquisition with double field-of-view (FoV) imaging capability. This extended FoV is realized by spatial multiplexing the object wavefront with distinct object information onto the faceplate of a digital image sensor. This multiplexing is achieved by inserting a cube beam splitter (CBS) in the object wavefront. The CBS is slanted to create two object wavefronts with two distinct FoVs that propagate in almost the same direction and accumulate near the image sensor, each carrying a different set of object information. During the reconstruction process, two different imaging areas corresponding to the two recorded FoVs can be obtained concurrently, and hence the desired information, including the phase, displacement/deformation, vibration, refractive index, etc. The single-shot acquisition is realized by principal component analysis (PCA) based computational method. The digital holographic system is used for imaging distinct areas of 3-D reflective objects recorded in a single multiplexed hologram and for studying dynamic phenomena such as displacement and vibration measurements. The proposed system could have a broad range of usages in exploring real-time dynamic phenomena with the advantages of single-shot acquisition and wider FoV.
Double Maxwellian foveated display
Raj Kumar, Myeong-Ho Choi, Rajveer Kaur, Jae-Hyeung Park
Journal of Information Display, 2025
Conventional near-eye displays (NEDs) used for augmented and virtual reality applications face the vergence-accommodation conflict (VAC), a mismatch between eye convergence and image focal depth, that causes discomfort to the wearer. To address this issue, Maxwellian displays have gained attention for their ability to project always-focused images. But the structure of the human vision system has high resolution in the foveal region, which reduces in the peripheral region, while the existing displays provide uniform resolution. If in a Maxwellian system, the resolution of the display can be tailored according to the requirements of the vision system, which will improve vision comfort and reduce the image computation time significantly. However, the optical realization of such a system is difficult. Here, we propose a novel guided double Maxwellian foveated NED using holographic optics to harness the benefits of both foveated and Maxwellian configurations. This optical design integrates a holographic pin-mirror waveguide to deliver high-resolution data in the foveal region and a concave mirror-based Maxwellian lightguide to display reduced-resolution information in the peripheral region. The proposed system is validated through optical simulation and experimental demonstration.
Performance evaluation of polygon-based holograms in terms of software, hardware and algorithms
Anuj Gupta, Fan Wang, Bhargab Das, Raj Kumar, David Blinder, Tomoyoshi Ito, Tomoyoshi Shimobaba
Optics Communications, 2024
Performance evaluation of Python and MATLAB for CGH generation using layer-based approach
Anuj Gupta, Bhargab Das, Raj Kumar
Journal of Optics India, 2024
Controlling the optical wavefronts for multiparametric sensing: Holography cum metamaterial centric perspectives
Deepak Kumar, Komal Sharma, Manoj Kumar, Raj Kumar
Optics and Laser Technology, 2024
Light origami multi-beam interference digital holographic microscope for live cell imaging
Manoj Kumar, Naru Yoneda, Lavlesh Pensia, Inbarasan Muniraj, Vijayakumar Anand, Raj Kumar, Takashi Murata, Yasuhiro Awatsuji, Osamu Matoba
Optics and Laser Technology, 2024
Measurement of anisotropy factor of nanoparticle embedded tumor phantoms for plasmonic photothermal therapeutics
Vikas, Raj Kumar, Sanjeev Soni
Journal of Biophotonics, 2024
Demonstration of a number of educational experiments on diffraction and interference of light using single-beam setup
Raj Kumar, Monika Rani
Optical Engineering, 2024
Effect of shrinkage in photopolymer film on the information transmitted through the holographic waveguide for near eye displays
Rajveer Kaur, Jae-Hyeung Park, Raj Kumar
Journal of the Optical Society of America A Optics and Image Science and Vision, 2024
Dual Field-of-View Off-Axis Spatially Multiplexed Digital Holography Using Fresnel’s Bi-Mirror
Lavlesh Pensia, Manoj Kumar, Raj Kumar
Sensors, 2024
Uniform holographic films of acrylamide/polyvinyl alcohol photopolymer using an automatic film applicator based on doctor blade technique
Heena, Komal Sharma, Kamlesh Kumar, Bhargab Das, Raj Kumar
Progress in Organic Coatings, 2024
Exit-pupil expansion in Maxwellian-type holographic-based waveguide near-eye displays
Rajveer Kaur, Raj Kumar
Proceedings of SPIE the International Society for Optical Engineering, 2024
Wide field 3D optical profilometry using a diffraction Lloyd’s mirror interferometer
Monika Rani, Raj Kumar
Applied Optics, 2023
A compact digital holographic system based on a multifunctional holographic optical element with improved resolution and field of view
Lavlesh Pensia, Manoj Kumar, Raj Kumar
Optics and Lasers in Engineering, 2023
Emerging scientific and industrial applications of digital holography: an overview
Raj Kumar, Gaurav Dwivedi
Engineering Research Express, 2023
Hanbury Brown–Twiss approach for imaging through a dynamic scattering medium
Sourav Chandra, Tushar Sarkar, Raj Kumar, Bhargab Das, Rakesh Kumar Singh
Optics Letters, 2023
Frugal techniques for optimization of CGH generation code
Anuj Gupta, Bhargab Das, Raj Kumar
Optics Continuum, 2023
Bragg degenerate model for fabrication of holographic waveguide-based near-eye displays
Rajveer Kaur, Lavlesh Pensia, Raj Kumar
Applied Optics, 2023
Automotive tire defect characterization with a portable digital holographic camera with an extended field of view
Sonali Chakraborty, Raj Kumar
Applied Optics, 2023
Highly Stable Vibration Measurements by Common-path off-axis Digital Holography
Manoj Kumar, Lavlesh Pensia, Raj Kumar
Optics and Lasers in Engineering, 2023
Computational-sampling-moiré-based on-machine alignment for freeform optics
Vinod Mishra, Nitin Dubey, M. P. Singh, Raj Kumar, Subrat Kar, Sunil Jha, Luke D. Mayer, Daewook Kim, Gufran S Khan
Optics Letters, 2023
Ultrasonic vibration–assisted magnetorheological hybrid finishing process for glass optics
Prabhat Kumar Baghel, Vinod Mishra, Raj Kumar, Gufran Sayeed Khan
International Journal of Advanced Manufacturing Technology, 2023
Dynamic change in optical properties of a nanoparticle embedded tumor phantom for plasmonic photothermal cancer therapeutics
Vikas, Raj Kumar, Sanjeev Soni
Journal of Biophotonics, 2023
Measurement of thin film thickness using diffraction Lloyd mirror interferometer
Monika Rani, Raj Kumar
Proceedings of SPIE the International Society for Optical Engineering, 2023
Techniques to Expand the Exit Pupil of Maxwellian Display: A Review †
Kaur Rajveer, Kumar Raj
Engineering Proceedings, 2023
Role of bandwidth of display source on information transmission in holographic waveguide based near-eye displays
Laser Science Ls 2023 in Proceedings Frontiers in Optics Laser Science 2023 Fio Ls Part of Frontiers in Optics Laser Science 2023, 2023
Role of bandwidth of display source on information transmission in holographic waveguide based near-eye displays
Rajveer Kaur, Raj Kumar
Frontiers in Optics Proceedings Frontiers in Optics Laser Science 2023 Fio Ls 2023, 2023
Cutting Edge Quality Assessment of Surgical Tools Using Knife-edge Interferometric NDT Technique
Monika Rani, Vinod Mishra, Raj Kumar
Frontiers in Optics Proceedings Frontiers in Optics Laser Science 2023 Fio Ls 2023, 2023
Cutting Edge Quality Assessment of Surgical Tools Using Knife-edge Interferometric NDT Technique
Laser Science Ls 2023 in Proceedings Frontiers in Optics Laser Science 2023 Fio Ls Part of Frontiers in Optics Laser Science 2023, 2023
Concentration-dependent photothermal conversion efficiency of gold nanoparticles under near-infrared laser and broadband irradiation
Vikas, Raj Kumar, Sanjeev Soni
Beilstein Journal of Nanotechnology, 2023
Pre-compensation model for shrinkage effect in photopolymer materials for holographic near eye displays
Rajveer Kaur, Jae-Hyeung Park, Raj Kumar
3D Image Acquisition and Display Technology Perception and Applications in Proceedings Optica Imaging Congress 3D Cosi Dh Flatoptics is Pcaop 2023, 2023
Combined effect of pin-mirror and concave mirror as out-couplers in Maxwellian holographic near-eye displays
Raj Kumar, Myeong-Ho Choi, Junyoung Jang, Jae-Hyeung Park
3D Image Acquisition and Display Technology Perception and Applications in Proceedings Optica Imaging Congress 3D Cosi Dh Flatoptics is Pcaop 2023, 2023
Study of a pH-Sensitive Hologram for Biosensing Applications †
Komal Sharma, Heena, Girish C. Mohanta, Raj Kumar
Engineering Proceedings, 2023
Field of View Enhancement of Dynamic Holographic Displays Using Algorithms, Devices, and Systems: A Review †
Monika Rani, Narmada Joshi, Bhargab Das, Raj Kumar
Engineering Proceedings, 2023
Comparative Study of Depth Estimation for 2D Scene Using Deep Learning Model
Arvind Kumar, Bhargab Das, Raj Kumar, Virendra Kumar
Lecture Notes in Networks and Systems, 2023
Nondestructive Inspection and Quantification of Soldering Defects in PCB Using an Autofocusing Digital Holographic Camera
Gaurav Dwivedi, Lavlesh Pensia, Viney Lohchab, Raj Kumar
IEEE Transactions on Instrumentation and Measurement, 2023
Looking through a dynamic scatterer
Jsap Optica Joint Symposia in Proceedings Jsap Optica Joint Symposia 2023 Abstracts Jsap 2023, 2023
Performance evaluation of different optical schemes for realization of holographic printers
Monika Rani, Navreen Kaur, Narmada Joshi, Pardeep Bhanot, Bhargab Das, Raj Kumar
Proceedings of SPIE the International Society for Optical Engineering, 2023
Single-shot off-axis digital holographic system with extended field-of-view by using multiplexing method
Manoj Kumar, Lavlesh Pensia, Raj Kumar
Scientific Reports, 2022
Role of incident beam shape on spatiotemporal photothermal temperatures for various nanoparticle concentrations for plasmonic photothermal cancer therapeutics
Vikas, Raj Kumar, Sanjeev Soni
Applied Nanoscience Switzerland, 2022
Effect of quality of opto-mechanical components on fringes of diffraction Lloyd mirror interferometer
Monika Rani, Ajay Shankar, Raj Kumar
Results in Optics, 2022
Characterisation of needle edge quality using diffraction pattern
Monika Rani, Vinod Mishra, Omendra Singh, Ajay Shankar, Raj Kumar
Measurement Journal of the International Measurement Confederation, 2022
On-machine tool wear estimation using a portable digital holographic camera
Gaurav Dwivedi, Lavlesh Pensia, Omendra Singh, Raj Kumar
Applied Physics B Lasers and Optics, 2022
Line contact ring magnetorheological finishing process for precision polishing of optics
Prabhat Kumar Baghel, Khushwant Singh Gavel, Gufran Sayeed Khan, Raj Kumar
Applied Optics, 2022
Noise free defect detection in ceramic tableware using a portable digital holographic camera
Lavlesh Pensia, Gaurav Dwivedi, Omendra Singh, Raj Kumar
Applied Optics, 2022
Investigation of the Plasmonic Interaction of Gold Nanoparticles Toward Plasmonic Photothermal Therapeutics
Vikas, Raj Kumar, Sanjeev Soni
Plasmonics, 2022
Magnification of portable digital holographic camera
Optics Infobase Conference Papers, 2022
Digital holographic camera with extended stochastic illumination for non-destructive inspection of silicon optics
Gaurav Dwivedi, Lavlesh Pensia, Sanjit K Debnath, Raj Kumar
Journal of Optics United Kingdom, 2022
Study of wavelength dependency on diffraction efficiency of volume holographic gratings based couplers in waveguide displays
Optics Infobase Conference Papers, 2022
A full-field optical crazimeter
Raj Kumar, Tushar Varshney, Tarun Yadav, Gaurav Dwivedi, S K Barve, Omendra Singh
Journal of Optics United Kingdom, 2021
Quantitative study of concentration-dependent optical characteristics of nanoparticle-embedded tumor
Vikas, Raj Kumar, Sanjeev Soni
Applied Nanoscience Switzerland, 2021
Effect of displacement in object plane on reconstructed image in lens-based digital holography
Lavlesh Pensia, Gaurav Dwivedi, Raj Kumar
Engineering Research Express, 2021
Non-destructive inspection and quantification of defects in plywood using a portable digital holographic camera
Lavlesh Pensia, Gaurav Dwivedi, Raj Kumar
Wood Science and Technology, 2021
Portable digital holographic camera featuring enhanced field of view and reduced exposure time
Raj Kumar, Gaurav Dwivedi, Omendra Singh
Optics and Lasers in Engineering, 2021
Performance evaluation of a digital holographic camera under variable source power and exposure time
Gaurav Dwivedi, Lavlesh Pensia, Sanjit K. Debnath, Raj Kumar
Applied Optics, 2021
Collimation Testing and Coherence Length Measurement of Short Coherence Laser Beams Using a Compact Holographic Shearing Interferometer
Rajiv Dubey, Raj Kumar
Springer Proceedings in Physics, 2021
Estimation of magnetorheological fluid constituent’s concentration for efficient finishing process
Prabhat Kumar Baghel, Raj Kumar
Materials and Manufacturing Processes, 2021
Expanding the Field of View in Off-Axis Digital Holography by Using A Holographic Optical Element
Optics Infobase Conference Papers, 2021
Estimation of Spectral and Thermal Effects on the Optical Beam for the Choice of a Lens for Photothermal Therapy
Vikas, Sanjeev Soni, Raj Kumar
Springer Proceedings in Physics, 2021
Role of domain size towards quantifying the optical properties of gold nanorods
Vikas ., Raj Kumar, Sanjeev Soni
Proceedings of SPIE the International Society for Optical Engineering, 2021
Crack detection in tableware items using digital holography interferometry
Optics Infobase Conference Papers, 2021
Effect of ultraviolet radiation exposure on optical nonlinearity and switching traits of SnO2 thin films deposited by thermal evaporation
Sandeep Yadav, Sonia Kumari, S.K. Ghoshal, Raj Kumar, S.K. Chaudhary, Devendra Mohan
Optics and Laser Technology, 2021
Erratum: Collimation testing of laser beams having different diameters using compact holographic lateral shearing interferometer (Opt. Eng. (2019) 59: 10 (102404) DOI: 10.1117/1.OE.59.10.102404)
Rajiv Dubey, Raj Kumar
Optical Engineering, 2020
Collimation testing of laser beams having different diameters using compact holographic lateral shearing interferometer
Rajiv Dubey, Raj Kumar
Optical Engineering, 2020
Delamination testing of polyurethane pads adhered to polishing tool using a digital holographic nondestructive testing method
Gaurav Dwivedi, Anuj Sharma, Omendra Singh, Prabhat K. Baghel, Raj Kumar
Optical Engineering, 2020
Detection of crack in plywood using digital holography interferometry
Lavlesh Pensia, Gaurav Dwivedi, Raj Kumar
Optics Infobase Conference Papers, 2020
Comparison of sensitivity to beam collimation of the holographic shearing interferometer with the wedge plate shearing interferometer and the Talbot shearing interferometer
Rajiv Dubey, Raj Kumar
Journal of the Optical Society of America A Optics and Image Science and Vision, 2020
Revisit to comparison of numerical reconstruction of digital holograms using angular spectrum method and Fresnel diffraction method
Gaurav Dwivedi, Sanjit K. Debnath, Bhargab Das, Raj Kumar
Journal of Optics India, 2020
Analyzing Thermal Stress Distribution in Metallic Components Using Digital Holography
Gaurav Dwivedi, Raj Kumar
Springer Proceedings in Physics, 2020
Quality evaluation of reconstructed images in digital holography to analyze the effects of source power and exposure times
Optics Infobase Conference Papers, 2020
A simple setup for measurement of the coherence length of a laser diode using holographic optics
Rajiv Dubey, Raj Kumar
European Journal of Physics, 2019
Harmonics of drift tearing modes in Aditya tokamak
Joydeep Ghosh, Harshita Raj, R. L. Tanna, Tanmay Macwan, R. Kumar, S. Aich, P. K. Chattopadhyay, K. A. Jadeja, K. Patel, D. Raju, S. Jha, P. K. Atrey, U. Nagora, A. Sen, N. Bisai, R. Pal, Aditya Team
2019 Ursi Asia Pacific Radio Science Conference AP Rasc 2019, 2019
High contrast laser beam collimation testing using two proximately placed holographic optical elements
Rajkumar, Rajiv Dubey, Sanjit K Debnath, D P Chhachhia
Journal of Optics United Kingdom, 2018
Multi-functional system for persons with disabilities using electroencephalography signals of eye blink
Subhra Sankha Sarma, Piyush Kant, Anon Rajkumar
Current Science, 2018
Holographic diffuser for multichannel restricted displays
Indian Journal of Pure and Applied Physics, 2016
Explaining shape of two beam interference fringes using diffraction-Lloyd mirror interferometer
Rajkumar
Optics Infobase Conference Papers, 2016
Explaining shape of two beam interference fringes using diffraction-lloyd mirror interferometer
Optics Infobase Conference Papers, 2016
Explaining shape of two beam interference fringes using diffraction-Lloyd mirror interferometer
Optics Infobase Conference Papers, 2016
Explaining shape of two beam interference fringes using diffraction-Lloyd mirror interferometer
Optics Infobase Conference Papers, 2016
Explaining shape of two beam interference fringes using diffraction-Lloyd mirror interferometer
Optics Infobase Conference Papers, 2016
Explaining shape of two beam interference fringes using diffraction-Lloyd mirror interferometer
Optics Infobase Conference Papers, 2016
Explaining shape of two beam interference fringes using diffraction-Lloyd mirror interferometer
Optics Infobase Conference Papers, 2016
Explaining shape of two beam interference fringes using diffraction-Lloyd mirror interferometer
Optics Infobase Conference Papers, 2016
Scratch enhancement and measurement in periodic and non-periodic optical elements using digital holography
Sonia Verma, Subhra S Sarma, Rakesh Dhar, Rajkumar
Optik, 2015
Straight, conic and circular fringes in single interferogram
Rajkumar
European Journal of Physics, 2015
HOE for recording off-axis holograms of phase objects
Rajkumar, D. P. Chhachhia, Omendra Singh, Ravi Kant
Proceedings of SPIE the International Society for Optical Engineering, 2015
Optical fiber antenna generating spiral beam shapes
S. Sarkar Pal, S. K. Mondal, D. Kumbhakar, R. Kumar, A. Akula, R. Ghosh, R. Bhatnagar
Applied Physics Letters, 2014
Formation of circular fringes by interference of two boundary diffraction waves using holography
Raj Kumar, D. P. Chhachhia
Journal of the Optical Society of America A Optics and Image Science and Vision, 2013
Effects of pressure gradients on laser beam propagation through an optical window for tokamak plasma diagnostics
Raj Kumar, Ranjeet Singh, Kaushal Pandya, Ajai Kumar
Fusion Science and Technology, 2012
Interference and diffraction effects in folding mirror schlieren diffraction interferometer
R. Kumar
Applied Physics B Lasers and Optics, 2008
Structure of boundary diffraction wave revisited
R. Kumar
Applied Physics B Lasers and Optics, 2008
Holographic optics-based schlieren diffraction interferometer
Current Science, 2008
Comparative study of different Schlieren diffracting elements
Raj Kumar, Sushil K. Kaura, D. P. Chhachhia, D. Mohan, A. K. Aggarwal
Pramana Journal of Physics, 2008
Interferometric moiré pattern encoded security holograms with concealed phase object
Raj Kumar, A.K. Aggarwal
Optics Communications, 2007
Direct visualization of Young's boundary diffraction wave
Raj Kumar, Sushil K. Kaura, D.P. Chhachhia, A.K. Aggarwal
Optics Communications, 2007
Schlieren interferometric concealed coded security holograms
Indian Journal of Pure and Applied Physics, 2007
Interferometric key readable security holograms with secrete-codes
Raj Kumar, D Mohan, A K Aggarwal
Pramana Journal of Physics, 2007
Knife-edge diffraction pattern as an interference phenomenon: An experimental reality
Raj Kumar, S.K. Kaura, A.K. Sharma, D.P. Chhachhia, A.K. Aggarwal
Optics and Laser Technology, 2007
Folding mirror schlieren diffraction interferometer
Raj Kumar, D. P. Chhachhia, A. K. Aggarwal
Applied Optics, 2006
Retrieval of infinite-fringe mode information from a beam folding interferometer for direct phase visualization
Raj Kumar, D P Chhachhia, A K Aggarwal
Journal of Optics A Pure and Applied Optics, 2006
Simple, compact and cost-effective optical interferometer using a grating and holographic optics
Journal of Scientific and Industrial Research, 2004
Interferometry based security hologram readable with an encoded key hologram
Indian Journal of Pure and Applied Physics, 2004

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