Dr Samsheer Ali P T (original) (raw)
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Papers by Dr Samsheer Ali P T
Results in Optics, 2024
We demonstrate a single-shot digital holographic microscopy technique to improve the diffraction-... more We demonstrate a single-shot digital holographic microscopy technique to improve the diffraction-limited
resolution in two orthogonal orientations simultaneously by dual-channel orthogonal polarization multiplexing
approach. Orthogonally polarized two oblique beams are employed to illuminate the sample and two reference
beams with mutually orthogonal polarization are interfered with the object beams in a custom-designed Mach–
Zehnder configuration. This technique is potentially beneficial to encode high frequency sample information
from two orthogonal directions simultaneously in a single recorded hologram where the high frequency spectra
is synthesized by the selective spectral stitching. Thus, the resolution is enhanced along two orientations from
a single-shot hologram in this work. Both the simulation and experimental results are shown for the proposed
technique with around 2-fold resolution enhancement over the diffraction limit
Optics Express, Jan 28, 2013
Applied Optics, 2015
ABSTRACT We propose a method for carrying out three-dimensional (3D) display based on single-shot... more ABSTRACT We propose a method for carrying out three-dimensional (3D) display based on single-shot digital holography. The 3D display is realized from a digital hologram (DH) by displaying the complex function recovered through the constrained optimization approach on a phase-only spatial light modulator (SLM). A DH of a multiplane object is recorded in a near on-axis configuration, and the complex function corresponding to the object in the hologram plane is recovered. The recovered function is converted into a phase-only function, and it is displayed on a phase SLM. The optical reconstruction through simple diffraction from the SLM reproduced the 3D scene, and the image reconstructed at each plane has been observed.
Optics Express, 2013
We demonstrate a novel computational method for high resolution image recovery from a single digi... more We demonstrate a novel computational method for high resolution image recovery from a single digital hologram frame. The complex object field is obtained from the recorded hologram by solving a constrained optimization problem. This approach which is unlike the physical hologram replay process is shown to provide high quality image recovery even when the dc and the cross terms in the hologram overlap in the Fourier domain. Experimental results are shown for a Fresnel zone hologram of a resolution chart, intentionally recorded with a small off-axis reference beam angle. Excellent image recovery is observed without the presence of dc or twin image terms and with minimal speckle noise.
Optics Communications, 2014
We demonstrate quantitative phase imaging using single shot digital holography for a calibrated s... more We demonstrate quantitative phase imaging using single shot digital holography for a calibrated spiral phase object. A single frame of near on-axis digital hologram of a spiral phase plate is recorded and the complex object field in the hologram plane is retrieved using a constrained optimization approach. Experimental results show the feasibility of a quantitative phase imaging technique which has superior performance to conventional Fourier filtering methods. Single shot capability suggests that this method is suitable for holographic imaging of dynamic objects such as live biological cells.
We propose a method for carrying out three-dimensional (3D) display based on single-shot digital ... more We propose a method for carrying out three-dimensional (3D) display based on single-shot digital holography. The 3D display is realized from a digital hologram (DH) by displaying the complex function recovered through the constrained optimization approach on a phase-only spatial light modulator (SLM). A DH of a multiplane object is recorded in a near on-axis configuration, and the complex function corresponding to the object in the hologram plane is recovered. The recovered function is converted into a phase-only function, and it is displayed on a phase SLM. The optical reconstruction through simple diffraction from the SLM reproduced the 3D scene, and the image reconstructed at each plane has been observed.
Optics Communications, 2013
We demonstrate quantitative phase imaging using single shot digital holography for a calibrated s... more We demonstrate quantitative phase imaging using single shot digital holography for a calibrated spiral phase object. A single frame of near on-axis digital hologram of a spiral phase plate is recorded and the complex object field in the hologram plane is retrieved using a constrained optimization approach. Experimental results show the feasibility of a quantitative phase imaging technique which has superior performance to conventional Fourier filtering methods. Single shot capability suggests that this method is suitable for holographic imaging of dynamic objects such as live biological cells.
We propose a method to carry out quantitative phase contrast imaging using in-line digital hologr... more We propose a method to carry out quantitative phase contrast imaging using in-line digital holography. The phase shifting digital holography is implemented in a common-path in-line configuration with the help of diffraction from a phase grating displayed on a spatial light modulator. The phase shifted interferograms are recorded by shifting the grating within a selected area corresponding to the dc spot in the Fourier transform plane. The feasibility of method is verified by using a multimode fiber as phase object. The method addresses a number of challenges faced by existing methods and dispenses the need for special optics.
We propose a method for carrying out three-dimensional (3D) display based on single-shot digital ... more We propose a method for carrying out three-dimensional (3D) display based on single-shot digital holography. The 3D display is realized from a digital hologram (DH) by displaying the complex function recovered through the constrained optimization approach on a phase-only spatial light modulator (SLM). A DH of a multiplane object is recorded in a near on-axis configuration, and the complex function corresponding to the object in the hologram plane is recovered. The recovered function is converted into a phase-only function, and it is displayed on a phase SLM. The optical reconstruction through simple diffraction from the SLM reproduced the 3D scene, and the image reconstructed at each plane has been observed.
We propose a method to carry out quantitative phase contrast imaging using in-line digital hologr... more We propose a method to carry out quantitative phase contrast imaging using in-line digital holography. The phase shifting digital holography is implemented in a common-path in-line configuration with the help of diffraction from a phase grating displayed on a spatial light modulator. The phase shifted interferograms are recorded by shifting the grating within a selected area corresponding to the dc spot in the Fourier transform plane. The feasibility of method is verified by using a multimode fiber as phase object. The method addresses a number of challenges faced by existing methods and dispenses the need for special optics.
OPTICS EXPRESS, 2013
We demonstrate a novel computational method for high resolution image recovery from a single digi... more We demonstrate a novel computational method for high resolution image recovery from a single digital hologram frame. The complex object field is obtained from the recorded hologram by solving a constrained optimization problem. This approach which is unlike the physical hologram replay process is shown to provide high quality image recovery even when the dc and the cross terms in the hologram overlap in the Fourier domain. Experimental results are shown for a Fresnel zone hologram of a resolution chart, intentionally recorded with a small off-axis reference beam angle. Excellent image recovery is observed without the presence of dc or twin image terms and with minimal speckle noise.
Results in Optics, 2024
We demonstrate a single-shot digital holographic microscopy technique to improve the diffraction-... more We demonstrate a single-shot digital holographic microscopy technique to improve the diffraction-limited
resolution in two orthogonal orientations simultaneously by dual-channel orthogonal polarization multiplexing
approach. Orthogonally polarized two oblique beams are employed to illuminate the sample and two reference
beams with mutually orthogonal polarization are interfered with the object beams in a custom-designed Mach–
Zehnder configuration. This technique is potentially beneficial to encode high frequency sample information
from two orthogonal directions simultaneously in a single recorded hologram where the high frequency spectra
is synthesized by the selective spectral stitching. Thus, the resolution is enhanced along two orientations from
a single-shot hologram in this work. Both the simulation and experimental results are shown for the proposed
technique with around 2-fold resolution enhancement over the diffraction limit
Optics Express, Jan 28, 2013
Applied Optics, 2015
ABSTRACT We propose a method for carrying out three-dimensional (3D) display based on single-shot... more ABSTRACT We propose a method for carrying out three-dimensional (3D) display based on single-shot digital holography. The 3D display is realized from a digital hologram (DH) by displaying the complex function recovered through the constrained optimization approach on a phase-only spatial light modulator (SLM). A DH of a multiplane object is recorded in a near on-axis configuration, and the complex function corresponding to the object in the hologram plane is recovered. The recovered function is converted into a phase-only function, and it is displayed on a phase SLM. The optical reconstruction through simple diffraction from the SLM reproduced the 3D scene, and the image reconstructed at each plane has been observed.
Optics Express, 2013
We demonstrate a novel computational method for high resolution image recovery from a single digi... more We demonstrate a novel computational method for high resolution image recovery from a single digital hologram frame. The complex object field is obtained from the recorded hologram by solving a constrained optimization problem. This approach which is unlike the physical hologram replay process is shown to provide high quality image recovery even when the dc and the cross terms in the hologram overlap in the Fourier domain. Experimental results are shown for a Fresnel zone hologram of a resolution chart, intentionally recorded with a small off-axis reference beam angle. Excellent image recovery is observed without the presence of dc or twin image terms and with minimal speckle noise.
Optics Communications, 2014
We demonstrate quantitative phase imaging using single shot digital holography for a calibrated s... more We demonstrate quantitative phase imaging using single shot digital holography for a calibrated spiral phase object. A single frame of near on-axis digital hologram of a spiral phase plate is recorded and the complex object field in the hologram plane is retrieved using a constrained optimization approach. Experimental results show the feasibility of a quantitative phase imaging technique which has superior performance to conventional Fourier filtering methods. Single shot capability suggests that this method is suitable for holographic imaging of dynamic objects such as live biological cells.
We propose a method for carrying out three-dimensional (3D) display based on single-shot digital ... more We propose a method for carrying out three-dimensional (3D) display based on single-shot digital holography. The 3D display is realized from a digital hologram (DH) by displaying the complex function recovered through the constrained optimization approach on a phase-only spatial light modulator (SLM). A DH of a multiplane object is recorded in a near on-axis configuration, and the complex function corresponding to the object in the hologram plane is recovered. The recovered function is converted into a phase-only function, and it is displayed on a phase SLM. The optical reconstruction through simple diffraction from the SLM reproduced the 3D scene, and the image reconstructed at each plane has been observed.
Optics Communications, 2013
We demonstrate quantitative phase imaging using single shot digital holography for a calibrated s... more We demonstrate quantitative phase imaging using single shot digital holography for a calibrated spiral phase object. A single frame of near on-axis digital hologram of a spiral phase plate is recorded and the complex object field in the hologram plane is retrieved using a constrained optimization approach. Experimental results show the feasibility of a quantitative phase imaging technique which has superior performance to conventional Fourier filtering methods. Single shot capability suggests that this method is suitable for holographic imaging of dynamic objects such as live biological cells.
We propose a method to carry out quantitative phase contrast imaging using in-line digital hologr... more We propose a method to carry out quantitative phase contrast imaging using in-line digital holography. The phase shifting digital holography is implemented in a common-path in-line configuration with the help of diffraction from a phase grating displayed on a spatial light modulator. The phase shifted interferograms are recorded by shifting the grating within a selected area corresponding to the dc spot in the Fourier transform plane. The feasibility of method is verified by using a multimode fiber as phase object. The method addresses a number of challenges faced by existing methods and dispenses the need for special optics.
We propose a method for carrying out three-dimensional (3D) display based on single-shot digital ... more We propose a method for carrying out three-dimensional (3D) display based on single-shot digital holography. The 3D display is realized from a digital hologram (DH) by displaying the complex function recovered through the constrained optimization approach on a phase-only spatial light modulator (SLM). A DH of a multiplane object is recorded in a near on-axis configuration, and the complex function corresponding to the object in the hologram plane is recovered. The recovered function is converted into a phase-only function, and it is displayed on a phase SLM. The optical reconstruction through simple diffraction from the SLM reproduced the 3D scene, and the image reconstructed at each plane has been observed.
We propose a method to carry out quantitative phase contrast imaging using in-line digital hologr... more We propose a method to carry out quantitative phase contrast imaging using in-line digital holography. The phase shifting digital holography is implemented in a common-path in-line configuration with the help of diffraction from a phase grating displayed on a spatial light modulator. The phase shifted interferograms are recorded by shifting the grating within a selected area corresponding to the dc spot in the Fourier transform plane. The feasibility of method is verified by using a multimode fiber as phase object. The method addresses a number of challenges faced by existing methods and dispenses the need for special optics.
OPTICS EXPRESS, 2013
We demonstrate a novel computational method for high resolution image recovery from a single digi... more We demonstrate a novel computational method for high resolution image recovery from a single digital hologram frame. The complex object field is obtained from the recorded hologram by solving a constrained optimization problem. This approach which is unlike the physical hologram replay process is shown to provide high quality image recovery even when the dc and the cross terms in the hologram overlap in the Fourier domain. Experimental results are shown for a Fresnel zone hologram of a resolution chart, intentionally recorded with a small off-axis reference beam angle. Excellent image recovery is observed without the presence of dc or twin image terms and with minimal speckle noise.