Study on high temperature stability of off-axis aspherical collimator

The collimator is a kind of necessary optical instrument for camera in the assembly, adjustment, and test process. In order to meet the high precision camera test requirements within the temperature in a range of 20 degrees C +/- 10 degrees C, a set of off-axis aspherical collimator with high accuracy and high temperature stability is designed. Mirrors use silicon carbide materials. Collimator tube is made of Indium steel materials. After finite element analysis, difference value of the linear expansion coefficient kept within a certain range and reasonable reflector support and the collimator can keep accurate stability within a certain temperature range. After test, off-axis collimator with (Phi 400mm diameter and, 8m focal length at 20 degrees C +/- 10 degrees C, the wavefront aberration is kept in the range from 1/5 lambda (P-V, lambda=632.8nm) to 1/30 lambda(RMS).The precision of the collimator can meet design requirement.