As early as in 1905, Einstein proved that occur in light wave Doppler effect, Doppler, a scientist from Austria, 1842 Christian Johann [2] for the first time found that, in any way convey, due to the waves, receivers, and convey the medium or the movement of the scatterer, will make the change frequency, the Doppler frequency shift.In 1960, the birth of the first laser to investigate the doppler effect of light wave provides good monochromaticity, directivity, power strong light source.Cummins and Yeh in 1964 with a laser doppler velocity laminar flow distribution have been measured, since founding a new measurement speed of laser doppler skills, carry out the laser doppler velocimeter (LDV).Skills laser doppler velocimetry (LDV) is a kind of laser applied skills, is a measurement of the fluid or solid velocity of new skills, it has the non-contact measurement, high precision, small measuring point, fast dynamic echo, distinguish and measurable multidimensional speed direction and other advantages.Now, laser doppler frequency shift skills has been widely applied to the fluid mechanics, aerodynamics, incineration, biology and medical, aviation, aerospace, machinery, and industrial production, such as category of speed measurement and other relevant measurement.Laser guns skills has been a history of 40 years ago. |
