Publication
We present a MEMS infrared spectrometer for selective and quantitative chemical gas analysis. It contains a tunable optical filter of porous silicon that allows to measure the infrared absorption of a gas mixture at different wavelengths serially with only one single thermopile detector. This method eliminates drift of the sensor without any reference beam. The filter that measures typically 1.0 x 1.8 mm(2) is tilted by a microactuator to tune it. This wavelength modulation can replace a modulation of the source. Selective sensing of CO2 and CO by their absorption bands at 4.23 mum and 4.65 mum has been shown.
Tobias Kippenberg, Camille Sophie Brès, Davide Grassani, Clemens Herkommer, Eirini Tagkoudi