Current Optics and Photonics

Optical Society of Korea (한국광학회)
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Thermo-optical Analysis and Correction Method for an Optical Window in Low Temperature and Vacuum

  • Ruoyan Wang (School of Electronic and Optical Engineering, Nanjing University of Science and Technology) ;
  • Ruihu Ni (Realsil Microelectronics Inc.) ;
  • Zhishan Gao (School of Electronic and Optical Engineering, Nanjing University of Science and Technology) ;
  • Lingjie Wang (Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences) ;
  • Qun Yuan (School of Electronic and Optical Engineering, Nanjing University of Science and Technology)
  • Received : 2022.10.11
  • Accepted : 2023.01.25
  • Published : 2023.04.25
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Abstract

The optical window, as a part of the collimator system, is the connector between the outside light source and the optical system inside a vacuum tank. The temperature and pressure difference between the two sides of the optical window cause not only thermoelastic deformation, but also refractive-index irregularities. To suppress the influence of these two changes on the performance of the collimator system, thermo-optical analysis is employed. Coefficients that characterize the deformations and refractive-index distributions are derived through finite-element analysis, and then imported into the collimator system using a user-defined surface in ZEMAX. The temperature and pressure difference imposed on the window seriously degrade the system performance of the collimator. A decentered and tilted lens group is designed to correct both field aberrations and the thermal effects of the window. Through lens-interval adjustment of the lens group, the diffraction-limited performance of the collimator can be maintained with a vacuum level of 10-5 Pa and inside temperature ranging from -100 ℃ to 20 ℃.

Keywords

Acknowledgement

National Key Research and Development Program (2019YFB2005500); National Natural Science Foundation of China (62205148, 62175107, U1931120); Six talent peaks project in Jiangsu Province (RJFW-019); Foundation of key laboratory of optical system advanced manufacturing technology, Chinese academy of sciences (KLOMT190201); Foundation of Shanghai key laboratory of online test and control technology (ZX2021102).

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