Microscopic Origins of Catastrophic Optical Damage in Diode Lasers

Extremely early phases of the catastrophic optical damage (COD) process in 808-nm emitting GaAs/Al
_0.35
Ga
_0.65
As high-power diode lasers are prepared by the application of short single current pulses. Typical energy entries during these pulses are on the order of 100 nJ within several 100 ns. The resulting defect pattern is investigated by high-resolution microscopy. The root of the COD is found to be located at the waveguide of the laser structure. Analysis of material composition modifications as a result of early COD phase points to melting being involved in the process. During recrystallization, an Al-rich pattern is formed that encloses a volume of a few cube micron of severely damaged material.