Non-resonant MOEMS mirror for laser cavity-length tuning

Abstract

High resolution spectroscopy via tunable lasers usually requires CW operation with mode-hop-free wavelength tuning. To suppress mode hopping by laser resonator-length tuning, Fraunhofer IPMS developed a novel electrostatic non-resonant translational micromirror. The combination of this device with a MOEMS grating within an external-cavity MIR QCL results in a miniaturized module that meets the requirements of high-resolution spectroscopy. The translational micromirror features a 5-mm aperture, an arbitrary actuator stroke of up to 120 µm and multiple independent electrostatic actuators to compensate for tip or tilt up to 350 µrad. We compare characterization and FEA simulation data, demonstrating the unique characteristics and the operational capability for a variety of applications.