Study On Laser Doppler Velocimeter Based On CO₂ Lasers

Velocity of solid targets and velocity distribution of flowing fields can be measured by Laser Doppler Velocimeter(LDV) technology based on Doppler Effect. Compared with the traditional velocity-measuring methods such as air balloon speedometer and flow speed probe, LDV technology has many merits including non-influence on the movement of the targets, stable signals, high precision, adaptability in the foul conditions etc.. And this technology has been widely used in the fields of science, industry, iatrology etc.. As a kind of nice laser lamp-houses, CO₂ laser has many merits such as high gain, nice interference, high beam quality, nice emitting mode, high power. In present the technology of CO₂ laser is mature and there are many domestic units which can produce kinds of high-quality CO₂ lasers. In the mean time, CO₂ laser is widely used in many fields including military affairs, aviation, weather-reporting and laser machining. Compared with other lasers, higher power and larger interference length can be obtained by using CO₂ laser. And CO₂ laser is one of the windows of the air transfers. It's power loss in air transfers is lower than other laser's.The history of the LDV technology is reviewed in this article. Basic principle of...