4.3 μm quantum cascade detector in pixel configuration.

We present the design simulation and characterization of a quantum cascade detector operating at 4.3μm wavelength. Array integration and packaging processes were investigated.

Quantum cascade detector utilizing the diagonal-transition scheme for high quality cavities.

A diagonal optically active transition in a quantum cascade detector is introduced as optimization parameter to obtain quality factor matching between a photodetector and a cavity. A more diagonal transition yields both higher extraction efficiency and lower noise, while the reduction of the absorption strength is compensated by the resonant cavity. The theoretical limits of such a scheme are obtained, and the impact of losses and cavity processing variations are evaluated.

Quantum cascade lasers with a tilted facet utilizing the inherent polarization purity.

We report on quantum cascade lasers (QCLs) with a tilted facet utilizing their polarization property. Contrary to diode lasers, QCLs generate purely TM polarized light due to the intersubband selection rules. This property enables the utilization of reflectivity in terms of only TM polarized light (TM reflectivity).

Monolithically integrated mid-infrared lab-on-a-chip using plasmonics and quantum cascade structures.

The increasing demand of rapid sensing and diagnosis in remote areas requires the development of compact and cost-effective mid-infrared sensing devices. So far, all miniaturization concepts have been demonstrated with discrete optical components. Here we present a monolithically integrated sensor based on mid-infrared absorption spectroscopy.

Monolithically integrated mid-infrared quantum cascade laser and detector.

We demonstrate the monolithic integration of a mid-infrared laser and detector utilizing a bi-functional quantum cascade active region. When biased, this active region provides optical gain, while it can be used as a detector at zero bias. With our novel approach we can measure the light intensity of the laser on the same chip without the need of external lenses or detectors.