Speckle suppression in imaging velocity interferometer system for any reflector

Imaging velocity interferometer system for any reflector (VISAR) is a typical facility for diagnosing shock wave velocity in ICF experiments. Due to the using of lighting laser in the system, the obtained velocity streak images are affected by laser speckle, and the velocity analysis is influenced for this reason. The formation reason of the laser speckle in the system and the effect in velocity analysis are introduced in the paper. A low pass filter located at the Fourier frequency plane of the imaging system is used to filter the high frequency speckle noise. An optical path of the interferometer used in the VISAR is put forward and the real path is simulated. The results shown in the paper indicate that the filter used in the system obviously suppresses the speckle noise in the imaging VISAR.