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As is generally known, miniature infrared spectrometers have great potential, e. g. for process and environmental analytics or in medical applications. Many efforts are being made to shrink conventional spectrometers, such as FTIR or grating based devices. A more rigorous approach for miniaturization is the use of MEMS technologies. Based on an established design for the MWIR new MEMS Fabry-Perot filters and sensors with expanded spectral ranges in the LWIR have been developed. The range 5.5 - 8 m is particularly suited for the analysis of liquids. A dual-band sensor, which can be simultaneously tuned from 4 - 5 m and 8 - 11 m for the measurement of anesthetics and carbon dioxide has also been developed. A new material system is used to reduce internal stress in the reflector layer stack. Good results in terms of finesse ( 60) and transmittance ( 80 %) could be demonstrated. The hybrid integration of the filter in a pyroelectric detector results in very compact, robust and cost effective microspectrometers. FP filters with two moveable reflectors instead of only one reduce significantly the acceleration sensitivity and actuation voltage

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A tunable IR filter based on a Fabry-Perot interferometer with two movable reflectors is reported. The infrared filter can be tuned over a wavelength range from 8 m to 11 m with voltages lower than 63 V. The FWHM bandwidth is lower than 200 nm and the peak transmittance is larger than 70 %. Simulation and practical shock test, both showed that the device can withstand 1500 g, 0.5 ms shocks according to Mil-Std-883G, method 2002.4, test condition B. The new infrared filter measures 8.5 mm x 8.5 mm and is suitable for the integration in a TO-8 housing in combination with a broadband infrared detector. The design benefits from relatively low stiffness of the mirror suspensions, compensation of vibration and gravitation induced forces possibly influencing the central wavelength and much lower actuation voltages as a result. Both reflector carriers are movable and are actuated by electrostatic forces

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