Defect Imaging in Laser Diodes by Mapping Their Near-Infrared Emission

Abstract

We report additional infrared (IR) emission bands at about 1.0 eV and 1.4 eV from GaAs-based diode lasers that have their primary emission at 808 nm (1.53 eV). Four long-wavelength bands are observed. They are assigned to bandtail-related luminescence from the quantum wells (QW) as well as to interband-and deep-level-related luminescences from the GaAs substrates. Thermal radiation is detected below 0.4 eV as well. By using a thermocamera, the defect-related emission was mapped for different types of high-power diode lasers. The mechanisms causing enhanced IR emission from the devices and potential applications of this type of monitoring are addressed.