Multipoint velocity interferometer system for any reflector

A multipoint velocity interferometer system for any reflector (VISAR) has b een developed which can simultaneously measure velocity versus time histori es of two to six points on a target or different objects during dynamic com pression. A single-frequency laser beam is divided into two to six individu al beams that are transmitted into an experimental device by incident fiber s to illuminate measured points. Diffusely reflected laser beams from diffe rent measured points are separately collected by fiber detectors and guided by signal fibers into a common "push and pull" interfering cavity with the same delay etalon to interfere. This not only simplifies the system struct ure and the experimental operation, but also eliminates the system error am ong measured points and makes the system almost as small in volume as that of a single-point VISAR. The multipoint VISAR possesses all the advantages of the traditional single-point VISAR as well as the temporal and the space resolution ability. We have used it to monitor velocity histories of sever al points on a target in a few explosion experiments, and good experimental results were obtained. (C) 1999 American Institute of Physics. [S0034-6748 (99)04009-5].