Automatic damage test benches: from samples to large-aperture optical components

The functional lifetime of large aperture components used in high power lasers, like LIL and LMJ facilities, is mainly determined by laser damage measurements. Automatic damage test benches allow to obtain more data in less time than traditional tests. We present, first experimental procedures and statistical analysis made on small samples with mm-size beams, to determine damage densities and damage growth laws. The presented methods are the usual 1on1, Non1, Ron1 and Son1 tests and more specially the raster scan procedure. The tests and analysis are compared to other results obtained with larger beams (few cm2) on large optics. We show that the exact knowledge of each shot parameters (energy, surface and pulse duration) permits to determine the damage growth rate (and then to predict the lifetime of each optics), to precisely study self-focusing phenomenon and more to finely observe pre-damage-levels. In this way, the main parameters like fluence or intensity are associated to the observed phenomenon. Moreover laser beam diagnostics, many diagnostics used for the detection and the observation of damage occurrence are equally very important. It is also necessary to develop test procedures entirely computed which permit to scan all the surface of a component and to acquire in real time the beam parameters and the results of laser-matter interaction. Experimental results are reported to illustrate what could be achieved on an instrumented and automated facility.

[1]  Patricia Volto,et al.  Self-focusing and rear surface damage in a fused silica window at 1064 nm and 355 nm , 2003, SPIE Laser Damage.

[2]  Herve Bercegol,et al.  Growth of damage sites due to platinum inclusions in Nd-doped laser glass irradiated by the beam of a large-scale Nd:glass laser , 2003, SPIE Laser Damage.

[3]  Michael J. Runkel,et al.  Automated damage onset analysis techniques applied to KDP damage and the Zeus small-area damage test facility , 2000, Laser Damage.

[4]  Laurent Gallais,et al.  Comparison of numerical simulations with experiment on generation of craters in silica by a laser , 2003, SPIE Laser Damage.

[5]  Pierre Garrec,et al.  Automatic YAG damage test benches: additional possibilities , 1999, Laser Damage.

[6]  Pierre Garrec,et al.  R-on-1 automatic mapping: a new tool for laser damage testing , 1996, Laser Damage.

[7]  Michel A. Josse,et al.  Parametric study of the growth of damage sites on the rear surface of fused silica windows , 2003, SPIE Laser Damage.

[8]  Alberto Salleo,et al.  Crack propagation in fused silica during UV and IR ns-laser illumination , 1999 .

[9]  Stavros G. Demos,et al.  Mechanisms to explain damage growth in optical materials , 2000, SPIE Laser Damage.

[10]  Mark R. Kozlowski,et al.  Automated damage test facilities for materials development and production optic quality assurance at Lawrence Livermore National Laboratory , 1999, Laser Damage.

[11]  Mark R. Kozlowski,et al.  Laser damage performance of fused silica optical components measured on the beamlet laser at 351 nm , 1999, Laser Damage.

[12]  Pierre Garrec,et al.  Beam characterization: application to the laser damage threshold , 1999, Laser Damage.

[13]  P. Combis,et al.  Study of UV laser interaction with gold nanoparticles embedded in silica , 2002 .