Room temperature, watt-level emission at 3.3 μm in Sb-free InGaAs-AlAs quantum-cascade lasers

Full text: Recently, the need for compact sensors, capable of real-time concentration monitoring,has become crucial. In particular the 3-μm spectral region is relevant since the fundamental C-H,N-H and O-H stretching modes have strong resonances in this region. The unique possibility offered by quantum cascade lasers(QCLs) to tailor the emission frequency, makes them ideal as sources for these applications. Unfortunately for wavelengths smaller than 4 μm, the realization of QCLs is challenging using the standard material systems,due to the large conduction band discontinuity needed. In this work, we present for the first time a QCL design based on the InGaAs/AlInAs-AlAs on InP material system emitting at ∼3.3 μm. Lasers show room-temperature, Watt-level emission. Maximum operation temperature above 350K was observed. To date, no QCL with emission wavelength smaller than 3.6 μm was demonstrated in this material system for a temperature accessible by thermoelectric cooling. (author)