A micromachined stationary lamellar grating interferometer for Fourier transform spectroscopy

This paper reports a novel micromachined stationary lamellar grating interferometer for Fourier transform ( FT) based spectroscopy applications. The interferometer employs a set of tilted interdigitated light reflecting beams to produce an interferogram with spatially varying optical path difference (OPD) recorded by a line photodetector array. Due to the advantages including robustness and the absence of mechanical moving parts and optical beam splitters, the proposed spectrometer may be built in a relatively small volume and with moderate cost for wide-band radiation spectra measurement, fast time-resolved spectroscopy and for field use. The proposed stationary lamellar grating FT spectrometer was implemented using a silicon-on-insulator (SOI) micromachining process. The prototype spectrometer demonstrated a full width at half maximum (FWHM) spectral resolution of 2 nm at a wavelength of 532 nm and of 2.6 nm at 632.8 nm.