Mirror electrostatic actuation of a medium-infrared tuneable Fabry-Perot interferometer based on a surface micromachining process

A tuneable Fabry-Perot interferometer fabricated with a tailored surface micromachining process is presented in this work. The device based on a movable flat micromirror driven by electrostatic actuation, is intended for gas sensing applications and operates in the medium-infrared spectral range. The electrostatic actuation features of the proposed structure are presented showing that a flat and parallel displacement of the mobile mirror is obtained. The characterization of the optical transmittance of the structure shows that this displacement allows covering a range of the transmitted spectra between 3.5 and 5.0 μm.