Design of a temperature compensation birefringent filter based on thermo-optic effect for space solar exploration

This paper presents the studies on the temperature compensation of birefringent filtersfor space-based solar exploration(Hα 656.28 nm). The four-element Lyot filter has a thickness ratio of 1:2:4:8. The technique of temperature compensation of the birefringent filter is based on the complementary characteristics of thermo-optic coefficients between the Iceland spar and ADP birefringence crystals. This paper describes a procedure of designing an independent of temperature filter. This technique of temperature compensation has the advantage that the system does not have a complicated mechanical structure by selecting the appropriate ratio of length of two different birefringence crystals.