Phase-shift interference fringe generation system and method

Abstract

The invention provides a phase-shift interference fringe generation system and method. The generation system comprises a light source, a light splitting unit and a light combining unit, wherein the light source is capable of emitting linearly polarized light, the light splitting unit can split the light emitted by the light source into reference light and object light, the light combining unit cancombine the reference light and the object light, a reference light transmission path and an object light transmission path are formed between the light splitting unit and the light combining unit, the light output end of the light combining unit is provided with a polarization detector, and phase-shift interference fringes are generated through rotating the angle of the polarization detector. The generation method is based on the above generation system. According to the invention, the high-speed and high-precision four-step phase-shift interference fringe generation is realized, and the problems of low speed, high cost and poor precision of the previous phase-shift interference fringe generation devices are solved to a great extent. Meanwhile, the high-speed property of the device alsosolves the malignant problems such as inaccurate measurement caused by the change of the measurement environment to a certain extent.

Description

technical field [0001] The invention belongs to the field of digital holography, in particular to generation of interference fringes of digital holography. Background technique [0002] Digital holography is a method of digital light field reconstruction using the principle of optical interference and diffraction. It regards every point in three-dimensional space in the surface of an opaque object that reflects light or the internal structure of a transparent or translucent object that transmits light as a point light source. , through the mathematical formula of optical interference and diffraction, use the computer to calculate the light-wave phase of these point light sources, and realize nano-scale ultra-precise three-dimensional measurement of the surface of opaque objects or the shape of transparent and translucent objects according to the interferometry method. [0003] When performing digital holographic ultra-precise three-dimensional measurement, two steps are requ...

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Problems solved by technology

[0005] However, there are two disadvantages in the above method. First, to change the optical path of the reference light, a piezoelectric micro-deformation mirror is required, which is expensive; One hundred nanometers, for such a requirement, the deformation accuracy of the piezoelectric micro-deformable mirror is low, and the phase difference of the formed interference fringes cannot maintain an accurate 0.5pi, so high-precision three-dimensional measurement cannot be performed; the last four phase-shifted interference fringe images The shooting is not at the same time, and the shooting is slow due to the low deformation speed of the piezoelectric micro-deformable mirror. The process is easily affected by external factors such as air flow, environmental vibration, and temperature changes. For example, air flow will bring interference fringes change, so that the phase shift difference of the four interference fringes cannot maintain an accurate 0.5p i, which will have a great adverse effect on the measurement results and measurement accuracy

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