EAGER: Spatial and Spectral Beam Control of Angled-Cavity Distributed-Feedback Quantum Cascade Lasers

Northwestern University, Evanston IL

Investigators

Abstract

The objective of this research is to investigate the operation principle of a new type of broad-area semiconductor lasers, termed beta-type distributed feedback lasers. The approach involves numerical and experimental investigations of the lateral mode selection mechanism through the angled cavity and the longitudinal mode selection mechanism through the beta-type distributed feedback grating. The intellectual merit of the proposed research is that a deeper understanding about the mode selection mechanism of beta-type distributed feedback will be obtained. The lateral mode selection will be investigated as functions of the cavity tilt angle, ridge width, cavity length, and sidewall verticalness. The longitudinal mode selection will be studied by changing the coupling strength. Finally, the optimal design will be applied to the best quantum cascade gain medium to demonstrate the highest peak power in room temperature single mode operation. The broader impacts of the proposed research stem from the potential that the beta-type distributed feedback laser offers a cost effective approach for power scaling of all types of semiconductor lasers while maintaining excellent beam quality with single mode emission, which offers immense benefit to the society, given the current proliferation of semiconductor lasers in the consumer market. The result of the proposed research activity will be disseminated in peer reviewed journals, professional conferences, and non-technical publications. Some results will also be compiled into classroom materials for both graduate and undergraduate courses.