Development of III-V Terahertz Quantum Cascade Lasers

The purpose of this Phase I study is to develop quantum cascade laser (QCL) with terahertz (THz) emission. Terahertz photons have energies which lie in the regime between optical photons and high frequency radio waves and have many important commercial and military applications. In the QCL, quantum wells (QWs) and injection layers are grown in a III-V semiconductor superlattice. The QWs and barriers are specifically designed to create exacting quantum states and energies within the device. Levels at different energy states provide carrier transitions where stimulated emission and lasing can occur. By varying the design parameters of the superlattice the emission wavelength can be tuned in principle to arbitrarily long wavelengths. During the Phase I, we will design, grow, fabricate and test a prototype QCL based on the AlGaAs/GaAs material system. The follow on Phase II will serve to improve the device performance by optimizing the device design and utilizing other III-V semiconductor materials. Terahertz quantum cascade lasers (QCL) have a variety of potential commercial and military applications including space-based and short-range terrestrial or near earth communications, atmospheric sensing, and near object observation and spectroscopy monitoring of atmospheric pollutants.