MICPHIR

The goal of the MICPHIR project is to outclass the limitations of single frequency semiconductor and solid-state lasers in the mid-IR (2-3µm). It aims to develop a new functionnal photonic component, exhibiting high spatial/temporal coherence at high power, based on III-V Sb and GaAs semiconductor technologies (VCSEL, photonic cristal, membrane). The main target application is a compact multi-gas sensor based on Cavity Ring-Down Spectroscopy technique (CRDS). This system will allow to develop a gaz sensor for various applications such as environnment, chimatology, industrial security, biology and medecine. To overcome the limitations of DFB-based sensors, the MICPHIR consortium plans to develop a new Vertical-External-Cavity Surface Emitting Laser (VeCSEL), combining compactness, wide tunability, high power and high space/time coherence. An full physical study will be performed (wavefront quality, intensity noise, linewidth, dynamics) to extract the critical physical parameters. A VECSEL is a semiconductor laser composed of a 1/2 VCSEL - a high reflectivity mirror and a quantum-well gain region -, an air gap ~cm, and classically a concave dielectric mirror as output coupler to close the cavity. Previous work reported on a diode-pumped Mid-IR 2.3µm VeCSEL, exhibiting very interesting performances, outclassing most of commercial DFB diode laser properties. This VeCSEL emitted similar output power (200GHz) and narrow linewidth (100mW), keeping a TEM00 beam for large diameter (>100µm) together with a narrow linewidth, for system in harsh environnement (temperature); to solve the mode hoping problem, to stablize the light polarization being insensitive to feedback. These improvements will be obtained thanks to a new physical and technological ingredients: thermal management of the 1/2 VCSEL via bonding, new QW gain structures emitting up to 2.8µm, and also thanks to a GaAs based photonic-crystal/plasmonic mirror device (output coupler) with embedded new functionnalities. Among these properties, a tunable wavelength filter to avoid mode-hopping, and/or a plasmonic filter to ensure stable polarisation state; a diffractive lens based mirror to control and stabilize the fundamental transverse mode in a sub-mm cavity. In a second step, this device will be integrated in a silicon matrix based micro-system bench, allowing to obtain a robust fully functionnal laser micro-system for targeted applications. The future final goal is to test this micro-emitter into a high sensitivity mutligas CRDS optical system. The sensor would allow in-situ detection and analysis of species of interest : CH4, NH3, HF, NO2, CO, CO2, H2O isotopes. These new device concepts and properties can be extended to other spectral range for various photonic applciations.