All-Silicon Single-Layer Terahertz Grating for Angular and Linear Displacement Sensing

In this paper, an all-silicon single-layer terahertz (THz) grating combined with both static and deformable structures is proposed and experimentally demonstrated for simultaneously angular and linear displacement sensing. The experimental results illustrate an outstanding sensitivity for both angular and linear displacement, which are 14%/mrad and 13.6%/μm, within a linear operational range of 4 mrad and 4 μm, respectively. Based on its compatible fabrication tolerance with existing MEMS fabrication technology, this sub-wavelength grating sensor in THz range shows a potential mass manufacturing prospect. The simple fabrication process and superior dual-parameter sensitivity enable the proposed sensor to be considered as a promising technology for display, optical switching, and sensing applications.