Parallel flat crystal optical inhomogeneity absolute measurement method

Abstract

The invention discloses a parallel flat crystal optical inhomogeneity absolute measurement method. The method comprises the following steps: carrying out primary interference measurement on the working face of a first transmission reference flat crystal and a front surface of a to-be-measured parallel flat crystal; placing a reflective reference flat crystal behind the to-be-measured parallel flat crystal, and carrying out primary interference measurement on the working face of the first transmission reference flat crystal and the working face of the reflective reference flat crystal; carrying out primary interference measurement on the working face of the first transmission reference flat crystal and the rear surface of the to-be-measured parallel flat crystal; carrying out primary cavity interference measurement on the working face of the first transmission reference flat crystal and the working surface of the reflective reference flat crystal; replacing the first transmission reference flat crystal with a second transmission reference flat crystal, and carrying out primary interference measurement on the working face of the second transmission reference flat crystal and the working face of the first transmission reference flat crystal; carrying out primary interference measurement on the working face of the second transmission reference flat crystal and the working face of the reflective reference flat crystal; and synthesizing measurement results, to obtain the optical inhomogeneity of the to-be-measured parallel flat crystal. The method is simple, feasible, accurate and efficient, and the measured object is not restricted by the parallel degree of the front surface and the rear surface.

Description

technical field [0001] The invention belongs to the field of optical interferometry, in particular to an absolute measurement method of parallel flat crystal optical non-uniformity. Background technique [0002] Optical transmissive materials are an important part of optical materials, and optical inhomogeneity, as an important index to evaluate the performance of optical transmissive materials, reflects the inconsistency of the internal refractive index of the same optical material. The inconsistency of the refractive index inside the optical material will directly lead to the change of the transmitted wavefront, thereby changing the wave aberration of the optical system. Typically, 10 -6 The optical non-uniformity of the order of magnitude will introduce wave aberration of the wavelength order, so it is of great significance to the high-precision detection of the optical non-uniformity of optical components. [0003] Experts at home and abroad have done a lot of research...

AI Technical Summary

Problems solved by technology

For the detection of optical non-uniformity by the sticking plate measurement method, it is necessary to add two glass flat crystals with the same refractive index as the measured piece as the sticking plate. The non-uniformity of the liquid will also affect the measurement accuracy; the four-step interferometry method for the detection of optical non-uniformity requires that the wedge angle of the glass plate to be tested be controlled between 2 and 66 angle minutes, and the parallelism of the front and rear surfaces cannot be very high. The parallel flat crystal is tested; the short coherence interferometry method solves the problem of flat plate optical non-uniformity with good surface parallelism before and after high-precision measurement, but the measurement accuracy is affected by the spectral width of the light source; the wavelength-tuned Fourier analysis measurement method The surface shape and material uniformity information of the front and rear surfaces of the parallel flat crystal can be obtained through two measurements, but the instrument must use a semiconductor laser that can precisely adjust the wavelength as the light source, and requires special processing software, which cannot be widely used

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