Diffraction property low-light test system and method of acousto-optic tunable filter (AOTF)

Abstract

The invention discloses diffraction property low-light test system and method of an acousto-optic tunable filter (AOTF). The system comprises a monochromatic light source system, an optical signal modulation system, an optical system and an photoelectric detection system, wherein the monochromatic light source system can generate monochromatic light beams with continuous and adjustable wavelengths, the frequency modulation can be carried out on the monochromatic light beams by a light chopper after passing through a diaphragm orifice, and an alternating-current optical signal sequentially passes through a collimating lens, a polarizer and an optical filter to form single-wavelength collimated polarized light which is vertically incident to the AOTF; and converged zero-level light and diffracted light generated after driving are bent to different directions by a prism and respectively received by two photoelectric detectors, therefore, the diffraction property of the AOTF is analyzed. The device of the invention has simple principle and strong operability, and can satisfy the continuous wavelength test requirements of the AOTF and simultaneously greatly improve the test efficiency through automatic control software. The invention realizes the low-light condition detection aiming at the application requirement of the AOTF under the low light by utilizing a phase locking circuit and improves the test precision. The system realizes the independent test of the zero-level light and the diffracted light and improves the test accuracy.

Description

Technical field: [0001] The present invention relates to optical measurement technology, and specifically refers to an acousto-optic tunable filter diffraction performance test system under weak light conditions, which is used to measure the diffraction efficiency, spectral resolution, side lobe and Diffraction properties such as second harmonics. Background technique: [0002] Acousto-optic tunable filter (AOTF) is a narrow-band tunable filter, which is a spectroscopic device made according to the principle of acousto-optic interaction. Wavelength scanning is realized by changing the frequency-selective splitting wavelength of the RF driver applied to the crystal. At present, this technology has been widely used in non-imaging and imaging spectroscopy instruments. [0003] AOTF's spectroscopic principle: as attached figure 1 , attached figure 2 As shown, when a beam of polychromatic light passes through a high-frequency vibrating optically elastic crystal, monochromati...

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Problems solved by technology

However, this method also has its limitations. At present, this method is used to test the diffraction efficiency and spectral resolution manually, and the efficiency is low. It takes a lot of time to detect side lobes and second harmonics.

At the same time, the laser energy is strong, which cannot reflect the diffraction performance of AOTF under weak light conditions, and has limitations in meeting application requirements.

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