A linear diffraction grating interferometer with high accuracy

摘要

A new miniature nanometer interferometer using grating Doppler effect is developed. The principle of this interferometer can be attributed to the phase information encoded by the ±1st order diffractive light beams. Properly interfering these two light beams leads to modulation similar to Doppler frequency shift, which can be translated to displacement measurement via phase decoding. Because of the measurement standard of grating interferometer system is the grating pitch, compared to the commonly used laser interferometer, the diffractive grating system reduces the environment influences on measurement accuracy. The calibration experiment between grating and HP5529A has been implemented. The measurement results show this grating interferometer measurement system is applicable for higher accuracy in long stroke.