Progress in research on polarization calibration technology of photoelectric telescope instruments

[ China Instrument Network Instrument Development ] Recently, the team of the Institute of Optoelectronics Rao Changhui has made important progress in the polarization and calibration of ground-based large-caliber solar telescope instruments.

Solar explosive activity will have a major impact on the Earth and interplanetary space environment, including communication disruptions, information security incidents, high-latitude power system collapse, and damage to space probes. Most of the sun's activities are related to the solar magnetic field. The measurement of the solar magnetic field helps to study the physical mechanism of the phenomenon of solar corona heating, flare triggering, and coronal mass ejection, thus realizing early warning of catastrophic space weather.

In order to achieve accurate space environment monitoring and space weather forecasting, it is necessary to obtain observation data of large field of view high resolution in the solar active area. Since the intrinsic polarization of the solar atmosphere and the instrument's own instrument polarization overlap each other, accurate measurement of the intrinsic polarization of the solar atmosphere cannot be obtained without high-precision and effective separation. Therefore, high-precision calibration of the intrinsic polarization introduced by the solar telescope and its back-end instrument is a prerequisite for high-precision measurement of the intrinsic polarization of the solar atmosphere.

To achieve the above objectives, the solar polarization measurement is required to achieve higher measurement accuracy and sensitivity. However, the processing and assembly errors of the optical components in the polarization measuring system and the instrument polarization of the telescope system itself greatly reduce the accuracy of the polarization measurement. The solar atmospheric intrinsic polarization measurement mainly involves high-precision polarization detection technology and instrument polarization calibration technology. Currently, measurements of the solar magnetic field are typically performed using polarization measurements of specific solar Zeeman splitting lines.

Optoelectronics has conducted in-depth theoretical and applied research on the polarization and calibration of ground-based large-caliber solar telescope instruments, effectively solving the problem of instrument polarization measurement and calibration unsynchronization.

At the same time, Optoelectronics completed the design of the instrument polarization dynamic calibration scheme of the first 2-meter solar telescope-1.8m solar telescope in China, and proposed the specific implementation requirements from the perspective of engineering application. It is the polarization calibration of the 1.8m solar telescope and the future sun. The foundation for high-precision polarization and magnetic field detection in the atmosphere is laid.

(Source: China News Network, Chinese Academy of Sciences, China Knowledge Network)