Carrier Dynamics in Mid-Infrared Quantum Well Lasers Using Time-Resolved Photoluminescence

The objective of this research is to improve the performance of semiconductor quantum well lasers operating in the mid-infrared. Research in mid-infrared laser technology has uncovered numerous applications for commercial and government use. Many military applications require operation near room temperature with compact power supplies. Limiting factors for improving the efficiency of mid-infrared semiconductor lasers at elevated temperatures include non-radiative recombination and carrier relaxation. Carrier lifetimes are typically on the order of 5 nsec, therefore, recombination mechanisms and carrier relaxation times are difficult to measure directly. Time-resolved photoluminescence (TRPL), utilizing a non-linear wave mixing technique known as upconversion, is used to study the time evolution of carrier densities in semiconductor lasers. Carrier recombination and relaxation information is extracted from this data to further the understanding of how quantum well structures impact semiconductor laser performance.