Characterization of the tuning performance of a micro-machined Fabry–Pérot interferometer for thermal infrared

We developed a tunable surface-micromachined Fabry–Pérot interferometer for the thermal infrared spectral region of wavelengths 7–11 µm. The device is controlled through capacitive actuation with the maximum applied voltage near 30 V. The transmission characteristics, as a function of the tuning actuation, were recorded for several samples with a Fourier-transform infrared spectrometer. Two different device designs are compared in terms of the transmission peak width and height evolution along the actuation. Numerical simulations and the established analytical Airy expression are exploited in order to bridge the gap between an ideal-model performance and the measurement results. Emphasis in the analysis is on the movable mirror unidealities and their implications in the performance. Finally, we present example data recorded with a laboratory setup of a gas spectrometer, based on the device under study. (paper)