Enhancement of wavefront measurement sensitivity in a zonal wavefront sensor without curtailing the sensing speed

Kumar, Nagendra; Khare, Alika; Boruah, Bosanta R.

doi:10.1088/2040-8986/ac3890

Cited by 7 publications

(3 citation statements)

References 21 publications

(22 reference statements)

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“…In GAWS, the grating elements are implemented using a liquid crystal spatial light modulator (LCSLM) and impart several essential flexibilities i nto t he s ensor. [19][20][21][22][23] In GAWS, as shown in figure1, t he p hase o f t he i ncident b eam i s e xtracted by p assing t he b eam t hrough a n array of binary diffraction g ratings a nd e stimating t he c entroids o f t he d iffracted fo cal sp ots fo r a pl ane wavefront Further author information: (Send correspondence to Nagendra Kumar) E-mail: nagendra.kumar@stanford.edu, Telephone: +1 650 643 7694 (R1R2) and aberrated wavefront (A1A2). However, GAWS provides a programmable means of zonal wavefront estimation of an unknown wavefront.…”

Section: Introductionmentioning

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: Introductionmentioning

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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“…13 The 3D PSF of a widefield microscope can also be estimated without imaging any subresolution fluorescent bead using a Shack-Hartmann wavefront sensor by measuring the wavefront at the exit pupil of the image plane. [14][15][16][17][18][19][20] However, for a highly aberrated imaging system, the wavefront could not be measured accurately, which leads to approximation error in PSF estimation. The PSF of a widefield microscope can be estimated with adequate SNR by performing linear non-blind 3D deconvolution from the z-stack of a through a thin specimen.…”

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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Enhancement of wavefront measurement sensitivity in a zonal wavefront sensor without curtailing the sensing speed

Cited by 7 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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