Array detection in a holographic scanning microscope

Buddha, S S Goutam; Kalita, Ranjan; Boruah, Bosanta R.

doi:10.1016/j.optcom.2020.125339

Cited by 8 publications

(4 citation statements)

References 21 publications

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“…Computer generated holograms are used for constructing optical wavefronts from numerically specified objects while considering the physical phenomena of light diffraction and interference. Holograms are extensively used for several applications such as in imaging, [28][29][30][31] optical trapping, 32 data storage, 33 etc. This section describes the generation of binary holograms that can be created by the interference of two waves, i.e.…”

Section: Methods To Generate the Uniform Intensity Profilementioning

confidence: 99%

Improvement in wavefront measurement accuracy in grating array-based zonal wavefront sensors by modulating the intensity profile of the incident beam

Kumar¹,

Choudhury²,

Sherpa³

et al. 2023

Practical Holography XXXVII: Displays, Materials, and Applications

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The wavefront measurement accuracy of a grating array based zonal wavefront sensor (GAWS) can be affected by the non-uniform focal spot array and unwanted orders in the detector plane. The non-uniform focal spot array is the outcome of the non-uniform nature of the incident illumination beam’s intensity profile. This paper describes a method that dynamically modulates the laser beam’s intensity using computer generated holography, making the focal spot array uniform and eliminating unwanted spots in a detector plane, thereby enhancing the accuracy of the wavefront measurement. Here, we present proof-of-principle simulation results that demonstrate the working of the proposed improvements in GAWS.

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Section: Methods To Generate the Uniform Intensity Profilementioning

confidence: 99%

Improvement in wavefront measurement accuracy in grating array-based zonal wavefront sensors by modulating the intensity profile of the incident beam

Kumar¹,

Choudhury²,

Sherpa³

et al. 2023

Practical Holography XXXVII: Displays, Materials, and Applications

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“…4,5 Therefore, these modes find applications in testing optical systems, adaptive optics, wavefront sensing and free space optical (FSO) communication systems. [6][7][8][9] Zernike modes have been used in ophthalmology for corneal study, 10 wavefront corrections for surface and thickness profile mesurement of thin film 8,11,12 and wavefront estimation, 13,14 aberration correction in microscopy [15][16][17] and micromanipulation of optical trapping. 18,19 In all these applications, the orthogonal property is the primary reason for their use.…”

Section: Introductionmentioning

confidence: 99%

Orthogonality of Zernike modes in phase profiles estimated using Zonal wavefront sensor and transport of intensity phase retrieval method

Chauhan

Sherpa

Kumar³

et al. 2023

Quantitative Phase Imaging IX

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Zernike polynomials are orthogonal polynomials that form a complete basis set and can be easily used to describe aberrations present in an optical system. Zernike modes find applications in various fields like adaptive optics (AO), optical imaging, ophthalmology, free space optical (FSO) communication, etc. Since the modes are orthogonal, they can express any arbitrary wavefront as their linear combinations. The orthogonality of the modes enables the calculation of the expansion coefficients and suggests the independent behaviour of the Zernike mode. In this work, we numerically estimate the wavefront, defined as Zernike modes, using various state of the art phase retrieval methods. We use the Zonal wavefront sensor (ZWFS) and Transport of Intensity Equation (TIE) for phase reconstruction and then calculate the orthogonality between reconstructed Zernike modes. It is found that the reconstructed Zernike modes are not perfectly orthogonal, which is mainly due to the discrete representation of the Zernike modes. We further investigate how the change in the number of zones in a ZWFS affects orthogonality. We also simulate TIE to retrieve the phase and compare the orthogonality results with ZWFS. This study will be helpful in applications where a wavefront described using Zernike mode needs to be reconstructed, and improvement in the orthogonality is required, which is achieved by increasing the number of zones in the ZWFS and representing Zernike modes in a more continuous form.

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“…For a conventional microscope, the resolution limit is approximately half the wavelength of light used to image the object. [1][2][3][4][5] PSF plays an essential role in determining imaging performances such as the resolution evaluation, optical sectioning capability, microscope calibration and various post-acquisition image deconvolution. 2,6 Thus it is crucial to know accurate information about the PSF to optimize the imaging performance of an imaging system and to enhance the image by deconvolution.…”

Section: Introductionmentioning

confidence: 99%

“…In this paper, we estimate the experimental three-dimensional PSF of a widefield microscope by taking several z-stacks of an arbitrary target, followed by applying our 2D PSF estimation scheme to each z slice. [22][23][24] The 2D PSF estimation is based on the minimization of the least square error between the image of an arbitrary target, and the convolution of a stochastically constructed PSF array with the geometrical-optics predicted image of the target. In this work, we use a standard resolution test target whose geometrical-optics predicted image could be easily constructed.…”

Section: Introductionmentioning

confidence: 99%

Estimation of 3D point spread function of a widefield microscope by stochastic least square minimization method

Buddha¹,

Kumar²,

Konwar³

et al. 2023

Three-Dimensional and Multidimensional Microscopy: Image Acquisition and Processing XXX

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The point-spread function (PSF) plays a fundamental role in deciding the resolution of an optical microscope. One way to find the experimental PSF is to image sub-resolution nanobead. However, the PSF can also be approximated numerically by knowing the optical arrangement of the imaging system. In this paper, we estimate the experimental three-dimensional PSF of a widefield microscope by taking several z-stacks of an arbitrary target, followed by application of our 2D PSF estimation scheme to each z slice. Here we use a standard resolution test target as the arbitrary target whose geometrical-optics predicted image can be easily constructed.

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Array detection in a holographic scanning microscope

Cited by 8 publications

References 21 publications

Improvement in wavefront measurement accuracy in grating array-based zonal wavefront sensors by modulating the intensity profile of the incident beam

Improvement in wavefront measurement accuracy in grating array-based zonal wavefront sensors by modulating the intensity profile of the incident beam

Orthogonality of Zernike modes in phase profiles estimated using Zonal wavefront sensor and transport of intensity phase retrieval method

Estimation of 3D point spread function of a widefield microscope by stochastic least square minimization method

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