The combination of broadly tunable quantum cascade laser chips in an external cavity (EC-QCL) with a micro- electro-mechanical system (MEMS) scanner with integrated diffraction grating as wavelength-selective element allows for the development of extremely compact and robust spectroscopy systems. Resonant MOEMS grating scanners enable spectral tuning rates of hundreds of wavenumbers per millisecond and consequently broad-band spectroscopy with millisecond temporal resolution. Also non-resonant (quasistatic) MOEMS grating scanners are possible, providing scan rates of tens of Hz as well as static setting of arbitrary wavelengths, as common for mechanically driven EC lasers, while keeping the small MOEMS footprint, ruggedness, and low power consumption. Here, we give a progress report on the latest developments on MOEMS-based EC-QCLs made by Fraunhofer IAF and IPMS. We will highlight two of our latest developments: A non-resonant MOEMS EC-QCL version that allows arbitrary scan frequencies up to few ten Hertz, as well as static operation. Furthermore, we present the application of a resonantly driven cw-MOEMS-EC-QCL with cavity-length control to enable fast high-resolution spectroscopy over a spectral range of >100 cm-1, offering new possibilities for spectroscopy on complex gas mixtures.

M. Haertelt, S. Hugger, L. Butschek, C. Schilling, A. Merten, M. Schwarzenberg, A. Dreyhaupt, J. Grahmann, M. Rattunde, R. Ostendorf, "Advances of MOEMS-based external cavity QCLs," Proc. SPIE 10926, Quantum Sensing and Nano Electronics and Photonics XVI, 1092613 (11 February 2019) copyright 2019 Society of PhotoOptical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, dupplication of any material in this paper for fee or commercial puposes, or modification of the content of the paper are prohibited.