LASER DOPPLER DISPLACEMENT MEASUREMENT.

Based on current developments in laser radar technology, a new device, a Laser Doppler Displacement Meter (LDDM) has been developed. This device is an electro-optical assembly, which uses the Doppler shift of a laser frequency caused by the movement of a target to measure displacement accurately over a range of a few meters. The LDDM consists of a laser head, a retro-reflector, a processor and a display. Using the latest in microelectronic, electro-optic and optical heterodyning technologies, an LDDM provides a high-precision and low-cost alternative to submicrometer positioning. The key feature of the LDDM is that its performance compares with that of a laser interferometer, while its price compares with that of a linear encoder.