The Unterrainer group's research interests are semiconductor quantum structures for novel photonic devices, ultrafast lasers ad terahertz time domain spectroscopy, and two-dimensional materials and their interaction with light. The terahertz region of the electromagnetic spectrum is a frontier area for photonics research. This part of the electromagnetic spectrum has been less well explored and has been called the "terahertz gap" because of the lack of high-power, room-temperature sources and efficient detectors. The generation and detection of radiation in this frequency range is difficult. Scaling and extrapolating known concepts of the microwave or infrared ranges is, in general, not possible. However, solid state quantum devices, which allow the realization of quantum optical concepts, e.g. for lasers and photon emitters, are very promising radiation sources in the THz range.