A high-resolution displacement sensor based on a grating interferometer with the phase modulation technique

A high-resolution displacement sensor based on a grating interferometer with the phase modulation technique is demonstrated in this paper. The grating interferometer is formed with a grating and a mirror, which is fixed on a piezoelectric translator to generate phase modulation. The detected signal is intensity-modulated and processed with a lock-in amplifier for demodulation. Experimental results show that this displacement sensor has a displacement sensitivity of 19.8 mV nm −1 and a high-resolution displacement detection of 0.05 nm in the linear region.