Parametric study of laser-induced damage growth in fused silica optics with large beams at 351 nm. Part 2: fractal analysis.

The impact of laser fluence and pulse duration on both the rate and probability of growth of laser-induced damage sites has been reported and analyzed statistically in a companion paper. In this paper, we report and analyze the volume morphology of damage sites during the growth process in fused silica optical components, at 351 nm, under various laser fluence and pulse durations. Fractal analysis has been used to quantify the bulk damage morphology.

Parametric study of laser-induced damage growth in fused silica optics with large beams at 351 nm. Part 1: stochastic approach.

Both the rate and probability of the growth of laser-induced damage sites in fused silica depend on several parameters. In this two-part paper, we investigate the impact of the laser parameters on damage growth. In Part I, we present statistical measurements of damage growth at different energy densities, pulse durations, and initial damage sizes.

Large optics metrology for high-power lasers.

The Laser MégaJoule (LMJ) is a high-power laser dedicated to laser-plasma experiments. At the beginning of the project in the mid-1990s, an optical metrology laboratory was created at CEA to help accomplish all the steps in the construction of this laser. This paper proposes an overview of the capabilities of this metrology laboratory in four main fields: surface imperfections, photometry, laser damage measurement, and wavefront measurement.

Quantification of laser-induced damage growth using fractal analysis.

Lateral and longitudinal laser damage growth under subsequent irradiations at 351 nm in the nanosecond range from micrometric to millimetric scales is presented herein. Atypical behavior has been observed, showing the growth in the longitudinal direction, whereas the lateral growth does not evolve. We propose the use of fractal analysis to describe the evolution of the bulk damage morphology.