SBIR-STTR Award

In Phase I we propose to demonstrate a room temperature continuous wave QC laser at 4.5µm with high power (P>0.5W) and wall plug efficiency (?>5%). The data will be used to design a high performance QC laser with projected wall plug efficiency exceeding 15% in continuous mode operation at room temperature. Our goal is to fabricate, characterize and package the high efficiency lasers in Phase II of the proposed project, and use beam combining methods to increase powers to above 3.5 W by combining six 1W single emitters with an estimated coupling efficiency of 65%. Preliminary sensing experiments, laser frequency modulation studies, and modeling of beam combining will also be carried out in Phase I with currently available lower efficiency lasers. The high efficiency devices will be designed at various possible emission wavelengths, ranging from the MWIR (3-5µm) to the LWIR (8-12µm). Modeling will take care of the three main aspects of efficiency improvement: heat management optimization, optical loss minimization, and electrical power reduction. The final phase I results will lead to a feasibility evaluation for a high power packaged laser with multiple high efficiency emitters combined in one rugged and portable package with estimates of its remote sensing and modulation capabilities.

Keywords:
quantum cascade lasers, mid-infrared spectroscopy, IRCM, high power room temperature continuous emission, beam combining, remote sensing

The proposed application for phase II deals with the prototyping and demonstration of a blackbody laser source of high brightness capable of simulating targets of varying temperature. This will enable a flexible and powerful missile plume simulator that can be used in airborne laser systems for targeting and seeker tests. Quantum cascade lasers are ideal for simulating light sources in the mid- and long-wave infrared, because their high spectral energy density is equivalent to that of a very bright blackbody source. When the QC material is electrically pumped, energy is directly converted into infrared light with an electro-optical conversion efficiency in the spectral range of interest of about 5-10%, which is orders of magnitude higher than the efficiency of a thermal source, whose emission is spread over a very broad spectral range and not directional. This high brightness sources can be very versatile and can be designed to target specific emission characteristics according to the application requirements. The QC laser based approach to simulating a black body can be achieved using current technology. The approach is versatile and scalable. Our proposal will deliver a QCL based prototype version of a blackbody element for simulation tests at different blackbody temperatures.

Keywords:
Quantum Cascade Lasers, Laser Blackbody Simulators, Airborne Laser Systems