The two-dimension Laser Doppler speedometer with dual differential acoustooptic frequency shift uses helium neon laser as its light source. The incident optical path is composed of two pieces of 1/4 wave plates, a neutral beam splitter, four prisms, a set of polarization beam splitter, three acoustooptic devices, a three-channel frequency shift generator and an incident lens. The receiving optical path is composed of a receiving lens, a polarization divider and two optical detectors. The three channel frequency shift generator contains three sets of crystal oscillator and provides three groups of different frequencies collocation to obtain various shift frequencies. Advantage-Dual differential acoustooptic frequency shift device has been applied to said polarization two-dimension Laser speedometer with the result of decreasing cort, raising signal/noise ratio and expanding its application range. |