Small-sized radial shearing interferometer based on four-step phase-shifting theory

Abstract

The invention provides a small-sized radial shearing interferometer based on the four-step phase-shifting theory, comprising a polarizer (P1), a polarizing beam splitter (PBS), a beam reducer or expander system, a quarter-wave (QW) plate, a binary micro-polarizer array and a photosensor CCD (Charge-Coupled Device) camera, wherein the beam reducer or expander system comprises a first lens (L1) with the focus f1, a second lens (L2) with the focus f2 (f1 is not equal to f2), a first reflector (M1) and a second reflector (M2). According to the interferometer, an aberrated beam enters the small-sized radial shearing interferometer to form a pair of beams which are arranged on the same optical axis and have polarization directions vertical to each other and beam sizes reduced and expanded according to the same proportion, and the pair of beams are projected on the photosensitive surface of the CCD camera to form a single-frame interferogram after passing through a four-step phase shifter which comprises the quarter-wave plate (QW) and the binary micro-polarizer array. The small-sized radial shearing interferometer based on the four-step phase-shifting theory does not need a fully-flattened reference mirror, can be used in the field of wavefront sensing application such as adaptive optics, and can effectively suppress environmental disturbance due to the adoption of a complete common path structure, and has low environment requirements and stable interferogram.

Description

technical field

[0001] The invention relates to the technical field of a wavefront sensor for wavefront measurement based on an interferometry, in particular to a miniaturized radial shear interferometer based on a four-step phase-shifting principle. Background technique

[0002] Wavefront sensors based on the principle of interferometry have attracted extensive attention due to their high spatial resolution and high measurement accuracy. Typical interferometric wavefront sensors such as point diffraction interferometers, shearing interferometers, etc. Among them, the shearing interferometer has received a lot of research by researchers because of its high light energy utilization rate and common optical path structure to resist external interference.

[0003] In the patent "Common-optical path direction shear interferometer based on four-step spatial phase shift structure. Patent application number: 201010034142.3", the author proposed a common optical path direction shear...

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