中国科学院南京天文光学技术研究所机构知识库

Polarimetry plays an important role in the measurement of solar magnetic fields。We developed a high-sensitivity and high-accuracy polarimeter (HHP) based on nematic liquid crystal variable retarders (LCVRs), which has a compact setup and no mechanical moving parts。The system design and calibration methods are discussed in detail. The azimuth error of the transmission axis of the polarizer as well as the fast axes of the two LCVRs and the quarter-wave plate were determined using dedicated procedures。Linearly and circularly polarized light were employed to evaluate the performance of the HHP。The experimental results indicate that a polarimetric sensitivity of better than 5.7 × 10^-3 can be achieved by using a single short-exposure image, while an accuracy on the order of 10^-5 can be reached

by using a large number of short-exposure images。This makes the HHP a high-performance system that can be used with a ground-based solar telescope for high-precision solar magnetic field investigations。