A Novel MOEMS NIR Spectrometer

In order to detect luminous intensity of light signal in NIR (Near-infrared) wavelength range, a novel MOEMS(Micro-Opto-Electro-Mechanical Systems) NIR spectrometer is proposed in the paper. It uses DMD (Digital Micro-mirror Device) to band filter the input spectrum. The merits of DMD are small size, low price and high scan speed. Especially, when DMD acts as a Hadamard Transform encoding mask, the SNR (signal-to-noise-ratio) can be improved by multiplexing the light intensities. The structure and the theory of this spectrometer are analyzed. The Hadamard-S matrix and mask of 63-order and 127-order are designed. The output spectrum of the new spectrometer coincides with experimental result of Shimadzu spectrometer. The resolution of the new spectrometer is 19 nm over the spectral range between 900∼1700 nm while single scan time is only 2.4S. The SNR is 44.67:1. The size of optical path is 70mm × 130 mm, and it has a weight less than 1Kg. It can meet the requirement of real time measurement and portable application.