Laser-Induced Damage in Optical Materials: 2014
The High Energy Density Physics (HEDP) research group was in attendance for the International Society for Optics and Photonics (SPIE) Laser-Induced Damage in Optical Materials: 2014.
Measurement of femtosecond laser damage thresholds at mid-IR wavelengths
Laser-solid interaction with 60-80 fs pulses at 800, 1900, and 3600 nm wavelengths was studied. S on 1 femtosecond laser damage thresholds (LDT) of Si, Ge, ZnSe, and CaF2 were determined at midinfrared wavelengths for the first time. Mid IR LDT trend disagrees with prediction based on a two temperature model that scales LDT as monotonically increasing function of wavelength.
Laser-induced periodic surface structure (LIPSS) formation in germanium above laser damage fluence by mid-IR femtosecond laser irradiation
Laser induced surface periodic structures (LIPSS) were generated via interaction of multiple 80 femtosecond mid IR laser pulses (3 -10,000) with single crystal Ge targets. At 3600 nm wavelength, at ~4 J/cm2 peak fluence, both low and high frequency LIPSS are formed, which are oriented perpendicular to each other. Low frequency LIPSS tend to form at the most intense central region where as high frequency features surrounds the central feature.
Using particle-in-cell simulations to model femtosecond pulse laser damage of metals and dielectrics
We present the first Particle-In-Cell (PIC) simulations of the full laser damage process and resulting damage spot morphology, as well as the first implementation of the Lennard-Jones pair potential for a PIC code. We model the effect of a femtosecond pulse laser on metal and dielectric targets near and above the damage threshold and compare to recent experimental results. Using the code LSP, we model the laser-target interaction and the subsequent target evolution using a series of 2D3V simulations. A typical run models a 100 fs, 2 micron spot size laser at various intensities and wavelengths.