Optical Rotation of Noncollinear AOTF Temperature Drift and Wavelength Correction Strategy

Existing AOTF tuning relationship mostly ignores the optical rotation effect, but it will effect the accurate design of acousto-optic tunable filter, and will further influence its filtering performance, so the relationship between the specific rotation rate and diffraction wave length was deduced, then the AOTF tuning relationship considering the optical activity was acquired; aiming at temperature drift of AOTF diffraction wave under different temperature, therefore affecting the spectral resolution of AOTF, this article starting from the ultrasonic velocity influenced by temperature, the relationship between the wavelength and driving frequency under different temperatures was gained by analyzing, and the new method of frequency correction tracking diffracted wavelengths was put forward under different temperatures. According to AOTF tuning relationship considering the optical rotation, and considering the real-time tracking temperature, repeatedly conversion driving frequency will easily cause damage to the system, and will further affect the efficiency, so we adopted 10 degrees C as a period of temperature, within a period of using a driver frequency to adjust AOTF according to the medium temperature, and every period has the corresponding relation of driving frequency-diffraction wavelength. The paper described the specific measures for the implementation and made the corresponding experiment. The results showed that compared to no frequency correction with normal room temperature, the diffraction wavelength was close to the target wavelength operated by the frequency correction under the corresponding temperature, and the error of the correction method is 1 order of magnitude lower than that without correction. The method provides an important basis for high accuracy spectrum measurement with AOTF under different temperatures, which has important practical value.