Building Blocks for Time-Resolved Laser Emission in Mid-Infrared Quantum Well Lasers.

摘要

The objective of this research is to improve the performance of mid- infrared semiconductor quantum-well lasers. Lasers operating in the mid-infrared are useful for many Air Force applications which include infrared (IR) countermeasures in particular. Countermeasure applications require lasers that are compact, and able to emit at high powers while operating at room temperature. Limits to power increases are seen in the transverse modal development of laser oscillation. These modes typically form in the waveguiding active region contributing to the laser output. However, competing modes outside of this region also develop when the confining structural layers have the right characteristics. These competing modes may draw power away from the main lasing mode, causing efficiency to drop. Therefore, theoretical models indicate that these 'ghost' modes should be extinguished. The goal of this work is to incorporate antimony-based semiconductor laser devices into a time-resolved photoluminescence (TRPL) experiment to examine modal development immediately after excitation. TRPL utilizes a non-linear wave mixing technique known as frequency upconversion to resolve sub-picosecond luminescence occurrences after excitation. Modification to the experiment is performed to produce laser emission from five mid-IR semiconductor laser samples. Both spontaneous and stimulated emission spectra are recorded. Alignment of the experiment is also carried out to produce upconversion of the PL signal to prepare for the incorporation of laser emission.