EC tuning of a two color QCL active region design in the 3 to 4 μm region

摘要

The 3–4 μm spectral region is relevant since the fundamental C-H, N-H and O-H stretching modes have strong resonances in this region (e.g. Methane, Formaldehyde). This is important for applications like pollution control, breath analysis or detection of water contaminants. The unique possibility offered by quantum cascade lasers (QCLs) to tailor the emission frequency, makes them ideal sources for these applications. Unfortunately for wavelengths smaller than 4 μm, the realization of QCLs is challenging using the standard material systems for high power QCLs, due to the large conduction band discontinuity needed [1].