Speed ​​sport Flyer Fabry - Perot Interferometer Measurement Technology Research

Laser interferometry can measure the velocity histories of the reflected surface or the internal particles velocity histories of the materials under shock wave conditions. As a non-contact measuring technique, Laser interferometry become a standard optical measuring technique in the fields of shock waves physics and detonation physics, this technique has a good future in the fields of weapon design, new material science, physical geography of the internal earth and planets, and so on. This paper discussed the basic theory and main principle of the laser interferometry; and presented a new method for measuring the velocity of the fast moving flyer based on the selected frequency character of the optical resonant cavity, and also presented the precision and ranges of this measuring method. At last, the velocity of the Kapton flyer was monitored by this technique.From the theory analysis, Fabry-Perot (F-P) resonant cavity can look as a filter, it has different transmissivity for the light with different frequencies, it can select the frequencies by adjusting the space of the F-P resonant cavity, The effects of parameters of the Fabey-Perot optical resonator to the testing precision and testing area are calculated using Matlab programs. The distance can be changed by two techniques: using piezoelectric ceramic or controlling the temperatures. It is found that the frequencies of the transmitted laser can be chosen when the distance of the F-P resonator changes, i.e., the center of the laser frequencies can be transmitted by adjusting the distance of the F-P resonator.The flyer was driven by a electric exploding foil, the magnitude of its speed can reach up to 3Km/s within 100ns. The results agree with that of VISAR in the same state. It can be concluded that the moving speed of flyer can be measured quickly and easily by the newly developed thin cavity Fabry-Perot interferometer.Compared with the traditional technique of laser interferometers, the new device of thin cavity F-P laser interferometry has properties of shorter response time, lower-request to the electronic recorder, smaller bulk , simpler structure, low cost, et al. So it can be widely used in the Detonation and Shock Wave Physics experimental research.