Automatic measuring system for grating diffraction angle spectrum

Abstract

The invention discloses an automatic measuring system for a grating diffraction angle spectrum. The system comprises a laser source, a scanning turntable, a sample turntable, a photoelectric sensor, asensor bracket and a photoelectric signal detection device, wherein the laser source is placed on a bracket with adjustable height, the sensor bracket is used for bearing the photoelectric sensor, the sample turntable is used for bearing a grating to be detected, and the photoelectric signal detection device is configured to control the scanning turntable and the sample turntable to rotate at a preset rotation angle so as to adjust the incident angle of the grating to be detected and carry out grating diffraction angle spectrum scanning to obtain a grating diffraction angle spectrum measurement result. Diffraction angle spectrum measurement under different incident angles can be carried out, the diffraction efficiency of each level of the grating and the stray light condition between diffraction levels can be accurately measured, and the magnitude difference of diffraction light and stray light can be accurately reflected.

Description

technical field [0001] The invention relates to the technical field of optical measurement, and more specifically, to an automatic measurement system for grating diffraction angle spectrum. Background technique [0002] Diffraction grating is an important optical device that diffracts incident light into multiple orders through periodic grid lines. like figure 1 As shown, the collimated light beam with a wavelength of λ is diffracted after entering the grating at a certain angle, and the diffracted light of different orders has different diffraction angles θ in space m and different diffraction efficiencies η m (diffracted light intensity divided by incident light intensity). Diffraction angle spectrum refers to the distribution of light diffracted by the grating with the angle, which is closely related to the microscopic information of the grating. First, the grating period d can be calculated by substituting the measured diffraction angle into the grating equation; sec...

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Problems solved by technology

[0003] In the prior art, measuring the diffraction efficiency of the working order of the grating cannot meet the requirements of the diffraction angle spectrum measurement, such as patent application CN201711430637 (a grating diffraction efficiency test system and method) and patent application CN201611039171 (grating diffraction efficiency spectral measurement device and measurement method)

Since the grating is used for dispersion, only a specific diffraction order (that is, the working order, generally +1 order or -1 order) is often used, and the prior art is all about measuring the relationship between the diffraction efficiency of the grating working order and the wavelength. , to evaluate the effective wavelength range of the grating, but it is not possible to accurately measure the diffraction angle and diffraction efficiency of each order

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