Through the nonlinear coupling interactions between atomic waves, the structure appears as the matter wave gratings, and diffracts its surrounding atomic waves.

Design of quarter wave-plate using sinusoidal dielectric subwavelength gratings;

To resolve the contradiction between the measurement of micro-displace or high-accuracy detecting of micro-vibration of ultra-low frequency and the convenience of building and adjusting, a inverted differential 4f grating demodulation system of laser Doppler is put forward.