Parallelization of digital holographic wavefront sensing

Accurate segmented mirror wavefront sensing and control is essential for next-generation large aperture telescope system design. In this paper, a direct tip–tilt and piston error detection technique based on model-based phase retrieval with multiple defocused images is proposed for segmented mirror wavefront sensing. In our technique, the tip–tilt and piston error are represented by a basis consisting of three basic plane functions with respect to the x, y, and z axis so that they can be parameterized by the coefficients of these bases; the coefficients then are solved by a non-linear optimization method with the defocus multi-images. Simulation results show that the proposed technique is capable of measuring high dynamic range wavefront error reaching 7λ, while resulting in high detection accuracy. The algorithm is demonstrated as robust to noise by introducing phase parameterization. In comparison, the proposed tip–tilt and piston error detection approach is much easier to implement than many existing methods, which usually introduce extra sensors and devices, as it is a technique based on multiple images. These characteristics make it promising for the application of wavefront sensing and control in next-generation large aperture telescopes.

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Computational Method for Wavefront Sensing Based on Transport-Of-Intensity Equation

Photonics ◽

10.3390/photonics8060177 ◽

2021 ◽

Vol 8 (6) ◽

pp. 177

Author(s):

Iliya Gritsenko ◽

Michael Kovalev ◽

George Krasin ◽

Matvey Konoplyov ◽

Nikita Stsepuro

Keyword(s):

A Priori ◽

Spherical Wave ◽

Computational Method ◽

Optical Systems ◽

Radius Of Curvature ◽

Imaging Method ◽

Wavefront Sensing ◽

Phase Imaging ◽

Transport Of Intensity Equation ◽

Priori Information

Recently the transport-of-intensity equation as a phase imaging method turned out as an effective microscopy method that does not require the use of high-resolution optical systems and a priori information about the object. In this paper we propose a mathematical model that adapts the transport-of-intensity equation for the purpose of wavefront sensing of the given light wave. The analysis of the influence of the longitudinal displacement z and the step between intensity distributions measurements on the error in determining the wavefront radius of curvature of a spherical wave is carried out. The proposed method is compared with the traditional Shack–Hartmann method and the method based on computer-generated Fourier holograms. Numerical simulation showed that the proposed method allows measurement of the wavefront radius of curvature with radius of 40 mm and with accuracy of ~200 μm.

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