Wideband and coherent detection with mid-infrared optical combs

This thesis contains the results of my internship at Laboratoire de Physique de l'École Normale Superiéure, done with Quantum Devices group (QUAD). The team research exploits the concepts of quantum mechanics, dealing in particular with light-matter interaction, to conceive new opto-electronic devices and systems in the mid and far infrared. My work focuses on the study of quantum devices operating in the mid-infrared range, in particular at 9 μm wavelength. This range of radiation is of great interest for techniques such as thermal imaging and spectroscopy , but also free space communication and remote sensing : finding good detection methods at this wavelength is thus extremely important. To this purpose, the report starts with a brief introduction on photonic detectors, their issues and figures of merit, after which my personal contribution is presented. During mu internship I had the opportunity to work with a new, unique, ultra stable Frequency Comb laser. In the first part of my internship I used the frequency comb to perform the characterization in time and frequency domain of a room temperature Quantum Cascade Detector (QCD) fabricated by one member of the team; then I performed the active stabilization of a Distributed Feedback (DFB) Quantum Cascade Laser (QCL) on the Frequency Comb. Note that an important part of my work was devoted to setting up these two experiments from scratch, finding good alignment conditions and learning to work with mid-infrared optics. Being able to have a stable QCL is a fundamental step towards the study of ultra-sensitive heterodyne detection for remote sensing, i.e. for the realization of LIDAR experiments in the mid-infrared range.