Tunable Continuous Wave THz Source Based on a Room Temperature Quantum Cascade Laser

This proposal presents a new paradigm for compact, efficient, and tunable continuous wave (CW) THz light generation at room temperature. This type of THz source has numerous applications in basic science, as well as in explosive and drug detection, security screening (Tray imaging), astronomy/ astrophysics, and medical imaging. The small size of this source and potential for mass production may represent a future enabling technology for widespread access to the THz spectral region. Intellectual merit: The core elements of this project are: (1) Demonstration of a quantum cascade laser capable of room temperature CW operation with a high intrinsic THz nonlinearity; (2) The demonstration of a widely electrically tunable two frequency quantum cascade laser; (3) Realization of a room temperature, CW, tunable THz source in a compact, single-chip format. The various research topics necessary include modeling of intersubband gain and transport, c(2) engineering, thermal management, and laser cavity nonlinearities, all of which are active areas of investigation in the optoelectronic and physics communities. As such, the results of this investigation will be of interest to many people in these fields. In addition, progress on the THz source itself will be of interest to a much wider community of scientists, for a variety of spectroscopic and imaging applications. The PI’s background is extremely well matched to the proposed research, and all the required resources and expertise are available. Broader impact: With this research, we hope to solve many basic problems with existing THz sources. It will be small, operate at room temperature, and have an electrically tunable output frequency. The CW operation will simplify system implementation and allow for a greater variety of experiments to be performed. It can also be a drop-in replacement for existing THz sources in many imaging applications. With significant potential for mass production, the source can be made cheaply, similar to other semiconductor lasers. This will allow many more people access to THz sources for novel and unique research.