Thermal/ structural/optical integrated analysis on spatial heterodyne Raman spectrometer imaging lens

The portable spatial heterodyne Raman spectrometer integrates optical lens, interferometer, and thermal radiation devices such as detector and laser. Therefore, the spectrometer has a complex thermal environment, and the change of the ambient temperature can lead to the decline of optical system performance.Aiming at this problem, the method of thermal/ structural/optical (TSO) integrated analysis was used to study the influence of ambient temperature and thermal radiation devices on the performance of imaging lens. Based on the design of the optical system and mechanical structure of the spectrometer, the thermal-structure coupling model of the lens was established, and the changes of the lens spacing and the surface shape were obtained by simulation surface change imaging lens, the Zernike polynomial was used to fit their changes. Finally, the results were coupled in the optical design software to evaluate and analyze the imaging quality. The analysis results show that, in the working ambient temperature(-10℃~40℃), the design value of the modulation transfer function (MTF) at 76.9 lp/mm is better than 0.38, which meets the requirement of the portable spatial heterodyne Raman spectrometer.