Dr. Rakesh Kumar Singh Profile

Dr. Rakesh Kumar Singh

SPIE Involvement:

Editorial Board Member: Journal of Electronic Imaging | Author | Student Chapter Advisor

Publications (22)

Proceedings Article | 2 October 2024 Poster + Paper

Effects of defocusing on near-field intensity enhancement

Sarita ., Rajan Jha, Rakesh Kumar Singh

Proceedings Volume 13111, 131110C (2024) https://doi.org/10.1117/12.3028133

KEYWORDS: Nanoparticles, Near field, Laser scattering, Glasses, Silver, Mie scattering, Dielectrics, Zernike polynomials, Wavefront aberrations

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Proceedings Article | 7 June 2024 Presentation + Paper

Polarization digital holographic microscope for live cell imaging

Rakesh Kumar Singh, Shivam Kumar Chaubey, Mohit Rathor, Rupen Tamang, Biplob Koch

Proceedings Volume 13041, 1304109 (2024) https://doi.org/10.1117/12.3012683

KEYWORDS: Digital holography, Phase distribution, Microscopes, Fourier transforms, Polarization imaging

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Proceedings Article | 7 June 2024 Presentation + Paper

Enhanced wide-field off-axis holography based on intensity correlation

Amit Yadav, Gyanendra Sheoran, Takamasa Suzuki, Rakesh Kumar Singh

Proceedings Volume 13041, 1304104 (2024) https://doi.org/10.1117/12.3013634

KEYWORDS: Digital holography, Speckle, Image enhancement, Biomedical optics, Polarization

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Proceedings Article | 12 March 2024 Poster + Paper

Experimental measurement of complex elements of correlation matrix of polarized light

Sourav Chandra, Rakesh Kumar Singh

Proceedings Volume 12852, 128520C (2024) https://doi.org/10.1117/12.2692138

KEYWORDS: Matrices, Polarization, Polarized light, Spiral phase plates, Physical coherence, Phase distribution, Correlation function, Charge-coupled devices, Interferometry

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Proceedings Article | 20 September 2023 Paper

Second-order correlation of randomness for enhanced quality imaging

Manisha Dixit, Aditya Chandra Mandal, Rakesh Kumar Singh

Proceedings Volume 12608, 126081J (2023) https://doi.org/10.1117/12.3008161

KEYWORDS: Light sources and illumination, Imaging systems, Image quality, Speckle, Speckle pattern, Image enhancement, Diffraction limit, Image resolution, Diffraction, Point spread functions

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Proceedings Article | 20 September 2023 Paper

Holography with higher-order Stokes correlations

Rakesh Kumar Singh

Proceedings Volume 12608, 126080R (2023) https://doi.org/10.1117/12.3007905

KEYWORDS: Holography, Holograms, Polarization, Matrices, Stochastic processes, Scientific research, Physical coherence, Phase imaging, Digital holography, Design and modelling

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Proceedings Article | 9 October 2021 Presentation + Paper

Snapshot ghost diffraction imaging based on spatial averaging

Vinu R.V., Yanyan Huang, Ziyang Chen, Rakesh Kumar Singh, Jixiong Pu

Proceedings Volume 11896, 118960N (2021) https://doi.org/10.1117/12.2600803

KEYWORDS: Diffraction, Holograms, Correlation function, Holography, Light sources, Spatial light modulators, Beam splitters, Real time imaging

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Proceedings Article | 4 September 2018 Paper

Investigation of transverse motion of concealed scatterer using correlation of speckled speckles from static surface layer

Gokul Nair, Vinu R.V., Dinesh Naik, Michael Linde Jakobsen, Steen Hanson, Rakesh Kumar Singh

Proceedings Volume 10750, 107500A (2018) https://doi.org/10.1117/12.2320481

KEYWORDS: Speckle, Diffusers, Light scattering, Speckle pattern, Scattering, Blood circulation, Aerospace engineering, Dynamic light scattering, Skin, Laser scattering

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Proceedings Article | 24 April 2018 Paper

Effect of speckle pattern illumination on holographic recording and reconstruction

Vinu R. V., Darshika Singh, Jixiong Pu, Rakesh Kumar Singh

Proceedings Volume 10711, 107110Q (2018) https://doi.org/10.1117/12.2319390

KEYWORDS: Holography, Polarization, Speckle pattern, Speckle, Digital holography, Holograms, Wavefronts

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Proceedings Article | 21 February 2017 Presentation + Paper

Sparsity assisted approach for imaging from laser speckle

Vinu R. V., Charu Gaur, Kedar Khare, Rakesh Kumar Singh

Proceedings Volume 10074, 1007409 (2017) https://doi.org/10.1117/12.2251983

KEYWORDS: Speckle, Speckle imaging, Correlation function, Scattering, Light scattering, Laser scattering, Speckle pattern, Interferometry, Optical imaging, Tissue optics, Phase imaging, Image acquisition, Polarization

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Proceedings Article | 21 February 2017 Paper

Anisotropy imaging using polarization and angular multiplexing

Aparna V., Niraj Soni, Vinu R. V., Rakesh Kumar Singh

Proceedings Volume 10074, 100741P (2017) https://doi.org/10.1117/12.2251727

KEYWORDS: Chemical elements, Anisotropy, Multiplexing, Polarization, Imaging spectroscopy, Interferometers, Cell biology, Biophysics, Biomedical optics, Chemistry, Polarizers, Beam splitters, Wave plates, Sensors, Sagnac interferometers

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Proceedings Article | 15 June 2015 Paper

Jones matrix imaging for transparent and anisotropic sample

Niraj Kumar Soni, Atul Suresh Somkuwar, Rakesh Kumar Singh

Proceedings Volume 9654, 965420 (2015) https://doi.org/10.1117/12.2181657

KEYWORDS: Polarization, Wave plates, Polarizers, Interferometers, Beam splitters, Holography, Sagnac interferometers, Multiplexing, Fringe analysis, Physics

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Proceedings Article | 13 May 2013 Paper

Relation between vectorial source structure and coherence-polarization of light

Rakesh Singh, Dinesh Naik, Hitoshi Itou, Maruthi Brundavanam, Yoko Miyamoto, Mitsuo Takeda

Proceedings Volume 8788, 87880O (2013) https://doi.org/10.1117/12.2020842

KEYWORDS: Polarization, Glasses, Beam splitters, Light, Fringe analysis, Chemical elements, Speckle, Interferometers, Calibration, Stochastic processes

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Proceedings Article | 11 October 2012 Paper

Observation of spatial polarization structure near unfolding point of an optical vortex beam using a birefringent Mach-Zehnder interferometer

Maruthi Brundavanam, Yoko Miyamoto, Rakesh Singh, Dinesh Naik, Mitsuo Takeda, Ken'ichi Nakagawa

Proceedings Volume 8480, 848008 (2012) https://doi.org/10.1117/12.930564

KEYWORDS: Polarization, Crystals, Laser crystals, Interferometers, Optical vortices, Mach-Zehnder interferometers, Spiral phase plates, Beam propagation method, Wave plates, Charge-coupled devices

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Proceedings Article | 24 August 2011 Paper

Highly stable interferometric technique for polarization mapping

Dinesh Naik, Rakesh Kumar Singh, Hitoshi Itou, Yoko Miyamoto, Mitsuo Takeda

Proceedings Volume 8173, 817319 (2011) https://doi.org/10.1117/12.899853

KEYWORDS: Polarization, Calibration, Polarimetry, Interferometry, Fringe analysis, Prisms, Sagnac interferometers, Optical spheres, Interferometers, CCD cameras

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Proceedings Article | 27 May 2011 Paper

State of polarization mapping using a calibrated interferometric polarimeter

Dinesh Naik, Rakesh Kumar Singh, Hitoshi Itou, Yoko Miyamoto, Mitsuo Takeda

Proceedings Volume 8082, 80821T (2011) https://doi.org/10.1117/12.888964

KEYWORDS: Polarimetry, Polarization, Calibration, Interferometry, Fourier transforms, Fringe analysis, Sagnac interferometers, Interferometers, Optical components, Optical filters

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We propose a simple scheme for accurate state of polarization (SOP) mapping with an interferometric polarimeter using Fourier transform method of fringe analysis. In single shot polarimeters that use Fourier transform method of fringe analysis, a spatial carrier frequency is introduced in the fringes of recorded interferogram either by introducing the relative tilt between the sample beam under test and a reference beam, as demonstrated by Ohtsuka and Oka or by passing the sample beam through birefringent optical components such as Wollaston prisms as demonstrated by Oka and Kaneko. In this technique, the amount of spatial carrier frequency that enabled to filter different terms in the Fourier spectrum of the recorded interferogram had to be calibrated with the use of light with a known SOP. Even in this case, the spatial carrier frequency introduced in the recorded interferogram is influenced by the relative tilt of the beam used for calibration. To eliminate the linear phase introduced by spatial carrier frequency, usually the spectrum around the carrier frequency location in the Fourier transform is shifted and brought to the centre. During this process an error of a fraction of a pixel in the shifting of the spectrum after filtering to remove the linear phase introduced by spatial carrier frequency will drastically change the measured SOP of light. For accurate SOP mapping, it is important that we eliminate the artifacts and errors due to the spatial carrier frequency in the single shot polarimeter that are otherwise very promising. In the present work, we propose a Mach-Zehnder interferometric polarimeter that uses a common path Sagnac interferometer to generate reference beams with orthogonal state of polarization. By taking advantage of the inherent stability of the proposed common path Sagnac interferometer against surrounding vibrations and air turbulences, a simple calibration scheme using a light of known state of polarization is used to map the state of polarization with better accuracy.

Proceedings Article | 27 May 2011 Paper

Stokes holography for recording and reconstructing objects using polarization fringes

Rakesh Kumar Singh, Dinesh Naik, Hitoshi Itou, Yoko Miyamoto, Mitsuo Takeda

Proceedings Volume 8082, 808208 (2011) https://doi.org/10.1117/12.888963

KEYWORDS: Polarization, Glasses, Holography, Modulation, Electromagnetism, Holograms, Calibration, Scattering, Spherical lenses, Superposition

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Proceedings Article | 3 August 2010 Paper

Three-dimensional coherence holography using a commercial projector for display and incoherent illumination of a coherence hologram

Dinesh Naik, Takahiro Ezawa, Rakesh Singh, Yoko Miyamoto, Mitsuo Takeda

Proceedings Volume 7790, 77900Q (2010) https://doi.org/10.1117/12.858786

KEYWORDS: Holograms, Phase shifts, 3D image reconstruction, Holography, Interferometers, Coherence (optics), Projection systems, Shearing interferometers, Fourier transforms, Holographic interferometry

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Proceedings Article | 2 August 2010 Paper

Vortices in generalized Stokes parameters

Rakesh Singh, Dinesh Naik, Hitoshi Itou, Yoko Miyamoto, Mitsuo Takeda

Proceedings Volume 7782, 778209 (2010) https://doi.org/10.1117/12.859050

KEYWORDS: Polarization, Speckle, Electromagnetism, Sensors, Glasses, Spiral phase plates, Correlation function, Optical networks, Speckle pattern, Fourier transforms

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Proceedings Article | 5 June 2008 Paper

Analysis of accuracy of laser spot centroid estimation

Rakesh Singh, Joni Hattuniemi, Anssi Mäkynen

Proceedings Volume 7022, 702216 (2008) https://doi.org/10.1117/12.804104

KEYWORDS: Binary data, Error analysis, Speckle, Laser applications, Sensors, Distortion, Laser scattering, Scattering, Visualization, Distance measurement

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