title: Unveiling laser diode "fossil" and the dynamic analysis for heliotropic growth of catastrophic optical damage in high power laser diodes.
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.
authors.affiliation: TRUMPF Photonics, Inc., 2601 US Route 130 South, Cranbury, NJ 08512, USA.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: TRUMPF Photonics, Inc., 2601 US Route 130 South, Cranbury, NJ 08512, USA.
authors.forename: Yihan
authors.initials: Y
authors.lastname: Xiong
authors.affiliation: TRUMPF Photonics, Inc., 2601 US Route 130 South, Cranbury, NJ 08512, USA.
authors.forename: Haiyan
authors.initials: H
authors.lastname: An
authors.affiliation: TRUMPF Photonics, Inc., 2601 US Route 130 South, Cranbury, NJ 08512, USA.
authors.forename: Konstantin
authors.initials: K
authors.lastname: Boucke
authors.affiliation: TRUMPF Photonics, Inc., 2601 US Route 130 South, Cranbury, NJ 08512, USA.
authors.forename: Georg
authors.initials: G
authors.lastname: Treusch