Quantum Dot Microcavity Terahertz Laser

CBL Technologies and Stanford University propose to develop and characterize a unique quantum dot microdisk source for high-power laser operation in the low terahertz frequency regime. The source will be used in military applications such as chemical and biological sensing, imaging and communications, as well as emerging commercial applications in medicine and biology. The source contains two components: a gain component and a cavity component. The gain region is composed of self-assembled InAs quantum dots, where lasing occurs via an intersubband transition. Cavity structures are difficult in the terahertz regime, often either lossy or requiring excessively thick epitaxial layers. Our cavity is a high quality microdisk that can have quality factors in excess of 10000. For terahertz emission, the cavity diameter is large and easily fabricated. Since optical modes are present at the perimeter region of the large disks, a unique regrowth process is employed, selectively positioning quantum dots in the cavity mode region. Cavity and lasing simulations in the far infrared are completed, and Stanford has demonstrated early results. In this Phase 1, we will fabricate microdisk laser structures, characterize them in the near-infrared spectral region and extrapolate our results to the terahertz regime.