Dual-wavelength phase-shift interference-based method for measuring optical heterogeneity

Abstract

The invention discloses a dual-wavelength phase-shift interference-based method for measuring optical heterogeneity, wherein according to dispersion characteristics of a material, an interferometer which comprises two lasers with different optical wavelengths or a wavelength tunable laser is adopted, and refractive index heterogeneity of a sample to be measured under optical waves of two wavelengths is considered as the same as optical heterogeneity to be measured of the sample to be measured; a phase-shift interferogram of the sample to be measured under the optical waves of the two wavelengths before being put into the interferometer, and a phase-shift interferogram of the sample to be measured under the optical waves of the two wavelengths after being put into the interferometer are obtained by using phase-shifting interferometry;and physical light wave phase difference of the sample to be measured under the optical waves of the two wavelengths before / after being put into the interferometer is obtained by using a phase-shift interference phase recovery algorithm, and then the optical heterogeneity of the sample to be measured is obtained. According to the dual-wavelength phase-shift interference-based method for measuring the optical heterogeneity, system errors are automatically eliminated, the sample to be measured does not need to be adjusted during a process of measuring, no special requirements for surface shape, parallelism and machining accuracy of a front and a rear surfaces of the sample to be measured exist, thus the dual-wavelength phase-shift interference-based method for measuring the optical heterogeneity is a genuine absolute measuring method and has high measuring accuracy.

Description

technical field [0001] The invention relates to a method for measuring optical non-uniformity applied to optical glass, optical crystal and other optical materials and components, and belongs to the field of optical interference measurement. Background technique [0002] Phase-shift interferometry is a method to obtain the phase distribution of the light wave to be measured from the interference fringe. By using a precise phase shift device to sequentially introduce a specific phase shift value into the reference light wave, the position of the interference fringe is moved accordingly; During the phase shift process, the intensity distribution of the interference fringes is sampled and quantified by an area array photodetector (such as CCD, etc.), and stored in the frame memory, and the computer calculates the intensity of the light wave to be measured according to a certain mathematical model and algorithm. phase distribution. Phase-shifting interferometry is a commonly us...

AI Technical Summary

Problems solved by technology

This method is theoretically feasible, but the actual operation is difficult, and the adjustment and reset accuracy is very high, which is not easy to realize; and the system error cannot be deducted, which affects the measurement accuracy

This method has only principle and experimental research in the literature, and there is no commercial interferometer for actual measurement

Images