Portable Fourier transform infrared spectrometer based on an electrothermal MEMS mirror

This paper reports a micro Fourier transform infrared spectrometer (μFTIR), enabled by an innovative H-shaped electrothermal microelectromechanical systems (MEMS) mirror. The H-shaped MEMS mirror consists of 32 symmetrically-distributed three-level ladder bi-layer actuators, leading to large linear displacement with negligible tilting. The tilting angle of the mirror is as small as 0.06°, so there is no need of complex closed-loop control. The new μFTIR was applied in the composition prediction of soybeans, and the experimental results show that it can accurately measure the protein content.