A Fabry-Perot interferometer system for high-speed velocity measurement

The Fabry-Perot Velocity Interferometer System (F-PVIS) is designed and built for measuring the Doppler shift of light by recording positional changes in the interferometric pattern behind the Fabry-Perot interferometer. The velocity of a surface can be deduced from the Doppler shift which is caused by reflection on the moving surface. The finesse of the Fabry-Perot interferometer is found to be about 50. The F-PVIS is designed for measuring velocities of up to 20 km/s. The sensitivity of this system can be tuned by changing the distance between the Fabry-Perot mirrors. In the most sensitive state of operation, the accuracy is found to be better than 100 m/s while the time resolution is typically a few ns. In addition to the velocity measurement of the moving surface in the electric gun experiments, the fiber optic F-PVIS can be used for other measurements. By embedding the optical fiber into the target material, information about the shock wave inside the target can be achieved