Full path compensation laser feedback interferometry for remote ...

The accuracy of the existing laser feedback interferometry for measuring the remote target is limited.to several microns due to environmental disturbances. A novel approach is presented in this paper.based on the double-beam frequency-shift feedback of the laser, which can completely eliminate the.dead path errors and measure the displacement or vibration with accuracy at nanometer scale even.at a far measurement distance. The two beams emitted from one Nd:YVO4 crystal are incident on.the measur