Method for measuring phase delay of crystal broad spectrum

Abstract

The invention provides a method to measure the phase delay of wide spectra of a crystal, and belongs to the measuring technique of crystalline materials. The invention uses a bromine tungsten-arc lamp which can transmit ultraviolet and visible light as an illuminant, and adopts a double-beam spectrophotometer, a polarizer and an analyzer to continuously measure the transmission spectrum of a uniaxial crystal. In this way, the phase delay of the uniaxial crystal can be got from the transmittivity values under different wavelengths to achieve measurement of multiple wavelengths of phase delay. The invention overwhelms the defect of the traditional electrooptical modulation method, the optical heterodyne method and the Lambda / 4 wave plate method and so on that only phase delay of the uniaxial crystal under one single wavelength can be measured. The invention achieves the test of multiple wavelengths of phase delay, and the measuring method is timesaving, laborsaving, simple and reliable.

Description

Technical field: [0001] The invention relates to the measurement technology of crystal materials, in particular to a measurement method of crystal wide-spectrum phase delay. Background technique: [0002] As a functional material in modern laser application technology and polarization technology, birefringent crystals have been widely used in the fields of light polarization, modulation and nonlinear optics technology, especially for the production of various laser polarization devices, phase delay devices and Electro-optic modulation devices. In polarization technology, how to accurately and conveniently measure the phase retardation of crystals has always been concerned by people. Due to the dispersion characteristic of crystal birefringence, the phase retardation of crystal has obvious dependence on wavelength. In the prior art, the traditional electro-optical modulation method, optical heterodyne method, λ / 4 wave plate method, etc. are used to measure the crystal phase...

AI Technical Summary

Problems solved by technology

In the prior art, the traditional electro-optic modulation method, optical heterodyne method, λ / 4 wave plate method, etc. are used to measure the crystal phase delay, but the above-mentioned methods can only measure the uniaxial crystal phase delay of a single wavelength, such as Using the λ / 4 wave plate method to measure the phase retardation of the crystal requires a polarizer, an achromatic λ / 4 wave plate, and a polarizer to measure the crystal under test. The light source emits monochromatic light with a wavelength of λ. The polarizer becomes linearly polarized light, which becomes elliptically polarized light after passing through the measured crystal, and the phase difference in the direction of its long and short axes is π / 2. If it passes through the λ / 4 wave plate whose fast and slow axes coincide with the long and short axes of the ellipse, the The elliptically polarized light is compensated into a beam of linearly polarized light. If an analyzer is added after the λ / 4 wave plate, the extinction position will appear when the polarizer is rotated. The ellipsometric light can be obtained by measuring the rotation angle of the polarizer. Ellipticity angle, which indirectly obtains the phase delay of the tested part

Due to the limitation of the λ / 4 wave plate, only the phase delay at a single wavelength λ can be measured. It is difficult to realize multi-wavelength testing, because the λ / 4 wave plate at different wavelengths needs to be replaced to measure the phase delay of multiple wavelengths. , so the above method to measure the phase delay of the crystal is time-consuming and laborious

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