Abstract
Taking advantage of robust facet passivation, we unveil a laser "fossil" buried within a broad area laser diode (LD) cavity when the LD was damaged by applying a high current. For the first time, novel physical phenomena have been observed at these dramatically elevated energy densities within the nanoscale LD waveguide. The observation of the laser "fossil" is interpreted with different mechanisms, including: the origination of bulk catastrophic optical damage (COD) due to locally high energy densities, heliotropic COD growth, solid-liquid-gas phase transformations, strong longitudinal phonon cooling effect on the molten COD wave front, and the formation of patterns due to laser lateral modes. For the first time the COD propagation is analyzed temporally by an acoustic phonon bouncing model and the COD velocity is extrapolated to be exponentially decreasing from more than 800 μm/μs to a few μm/μs within a 20 μs time period as the energy density dissipates.