Monolithic Scalable Mid-Infrared Phase-Locked Laser Array

The technical objectives of this proposal are: 1) Design a metal/semiconductor grating-based (i.e., substrate-emitting) Grating-Coupled Surface-Emitting Distributed Feedback Quantum Cascade Laser (GCSE-DFB QCL) emitting at 4.6 microns with high beam quality; and 2) Demonstrate a GCSE-DFB QCL emitting at 4.6 microns with single-lobe-beam operation and high beam quality, under CW operation. It is the goal of this program to develop a GCSE-DFB QCL single-stripe device which will operate in a single, diffraction-limited lobe (both longitudinally and laterally) under CW operation to moderately high (~ 0.5 W) output powers. Tapered-active, deep-well QC lasers will be used, since they suppress carrier leakage out of active regions, resulting in electro-optic characteristics much less temperature sensitive than for conventional QC devices; thus allowing for significant increases in average power and wallplug efficiency.