Intersubband Emitters: GaAs-based Quantum-Cascade Lasers

The correlation between the emission frequency and the location on the wafer due to an inhomogeneous growth rate across the wafer was investigated for GaAs/AlAs terahertz (THz) quantum-cascade lasers (QCLs) using experiments and simulations. For several wafers, we observe a blue shift of the...

Terahertz (THz) quantum-cascade lasers (QCLs) based on GaAs/AlAs heterostructures have been developed for application-defined emission frequencies between 3.4 and 5.0 THz. These THz QCLs can be used as local oscillators in airborne or satellite-based astronomical instruments or as radiation sources...

We have realized GaAs/AlAs quantum-cascade lasers operating at 4.75 THz exhibiting more than three times higher wall plug efficiencies than GaAs/Al_0.25Ga_0.75As lasers with an almost identical design. The novel materials system for terahertz quantum-cascade lasers is expected to facilitate a new...

For astronomers, terahertz radiation provides new insights in the investigation of so-called cold matter. This kind of matter does not emit visible light such as the stars, but electromagnetic radiation in the infrared to microwave range. The German Aerospace Center (DLR) measures such emission...

We report on the development of a THz quantum-cascade laser (QCL), which will be used as the local oscillator in the heterodyne spectrometer GREAT (German Receiver for Astronomy at Terahertz Frequencies) on board of SOFIA, the Stratospheric Observatory for Infrared Astronomy, for the investigation...

Terahertz quantum-cascade lasers (THz QCLs) are promising far-infrared sources for various applications such as local oscillators in heterodyne detectors. This requires a combination of sufficient output power, continuous-wave (cw) operation in small-sized cryocoolers, and single-mode emission at...