A concave MOEMS scanning diffraction grating for infrared micro-spectrometer applications

Abstract

An imaging scanning diffraction grating suitable for the development of portable, low-cost infrared (IR) spectrometers is presented. The 2 mm-diameter resonant MEMS scanner can be integrated in a modified, more compact version of the Czerny-Turner dispersive spectrometer with a single element detector. A novel approach towards the incorporation of a reflective diffraction grating on a micro-scanner using the standard SOIMUMPsTM process is proposed. Furthermore, imaging of the diffracted beam is achieved directly by the scanning grating, utilizing the thermal stress mismatch between the silicon device layer and the reflective metal layer. It is demonstrated that a micro-spectrometer design based on the proposed scanning grating is capable of sampling a wavelength range of 1.14μm in 0.5 ms at a drive voltage amplitude of 30 V.