Output facet heating mechanism for uncoated high power long wave infrared quantum cascade lasers
Abstract
Output facet temperatures of an uncoated high power continuous-wave quantum cascade laser (QCL) emitting at 8.5 μm were measured by using micro-Raman thermometry. The rate of the measured temperature changes with the injected electrical power increased from 6.5 K/W below the laser threshold to 12.3 K/W above the threshold. In addition, the measured temperature rise exceeded 220 K at an optical power of 0.9 W, well above the model projections based only on Joule heating. Facet oxidation was characterized via x-ray photoelectron spectroscopy measurements at incremental etch depths. While the oxidation reactions of InP and Ga were observed only at the surface level, the measured penetration of native Al2O3 was ∼24 nm. COMSOL thermal modeling demonstrated that light reabsorption by the native Al2O3 layer could well explain the additional temperature rise above the threshold. These results suggest that facet oxidation must be addressed to ensure the reliability of high-power long wave infrared QCLs.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 01, 2020
- Source ID
- 10.1063/5.0012657
Entities
People
- Arkadiy Lyakh
- Dagan Hathaway
- Enrique Sanchez
- Hong Shu
- Matthew Suttinger
- Monas Shahzad
- Rowel Go
- Sudipta Seal
- Tamil S. Sakthivel
Organizations
- Air Force Office of Scientific Research
- National Science Foundation
- Naval Air Systems Command
- University of Central Florida