Novel all-light optically readable thermal imaging sensor based on MEMS technology

This paper presents a novel all-light optically readable thermal imaging sensor based on the bulk-MEMS technology. The sensor contains a focal plane array (FPA) consisting of m × n movable micromirrors supported by bimaterial beams. As infrared radiation applied on FPA, a temperature gradient generated on the bimaterial beams leads to the deflection of beams and resulting in proportional displacement of this movable micromirror. A visible optical system is used to measure the displacement of the movable micromirrors of the FPA using Fabry-Perot interferometry. Our Al/SiO₂ micromirror structure is optimized to achieve a thermo-mechanical sensitivity of 10^-8m/K. The FPA consisting of 50× 50 movable micromirror array has been successfully fabricated by using bulk MEMS technology.