Development of Quantum Cascade Laser Heterostructures for Mid-Infrared (4-5 Micron) Atmospheric Transmission

This proposal is aimed at further improving the design of quantum cascade lasers for ambient temperature free-space communication in the mid-infrared (4< lambda <5 microns). In Phase I, we established a phenomenological model for the sources of inefficiencies in short wavelength quantum cascade lasers. In a relatively straightforward design improvement based on this model, we were able to demonstrate much improved average power and high duty cycle operation. In Phase II, we will use a systematic approach to further minimize the limiting factors to high duty cycle performance of these lasers at room temperature. For greater versatility, an optional goal is to maximize the power efficiency of the laser in order to demonstrate continuous wave operation as well. A second option will investigate the packaging of these lasers into a battery-driver pointer module which can be used as part of communications transceiver. Provided further interest is available, a final option is to investigate high power, single-mode operation of these lasers.