High-Performance Quantum Cascade Lasers Grown by Metal-Organic Vapor Phase Epitaxy and Their Applications to Trace Gas Sensing

We present an overview of our results on the design, material growth, device characterization, and spectroscopic applications of MOVPE-grown quantum cascade lasers (QCLs). These devices are capable of room-temperature (RT) continuous-wave operation and high power emission. The first section focuses on growth of laser material, device fabrication, and quantum design The second section discusses RT pulsed operation, in particular the doping dependence of laser performance and broadband emission. Near-field measurements performed on the devices´ facets correlating lateral modes to device size are also discussed. Section III deals with continuous-wave high-temperature operation from lasers with different active region designs, including their spectral characteristics and in the emergence of coherent phenomena at high power levels. Section IV analyses the devices thermal dissipation capabilities, while in Section V we report reliability data. The final section focuses on spectroscopic applications and tunability. Optofluidic narrow ridge lasers and their application to chemical sensing are reported along with recent data on a broadband on chip spectrometer consisting of individually addressable distributed feedback QCLs. Various spectroscopic techniques and in particular quartz-enhanced photoacoustic absorption spectroscopy and its use in gas sensing systems are discussed. Finally, optofluidic narrow ridge lasers and their applications to fluid sensing are presented.