Aiming at the problem of large volume and low resolution of displacement sensor

this paper designs a nano-grating structure for in-plane displacement detection. The coupled wave theory is used to illustrate the diffraction properties of the grating. The grating gap

grating period

grating duty cycle and incident wavelength of the two-layer grating are optimized and analyzed by Gsolver software. The effects of the in-plane displacement of the double-layer grating on the diffraction efficiency under various parameters are studied. Finally

a set of displacement-sensitive grating structures is obtained. The simulation results show that the light transmission characteristics of the double-layered grating are better when the two-layer grating gap is 200 nm

the grating thickness is 390 nm

the grating period is 800 nm

and the incident light wavelength is 850 nm. The in-plane micro-displacement of the grating can be obtained by detecting changes in transmitted light intensity.