Case Study: Lawrence Livermore National Laboratory achieves precision repair of fused silica optics with COMSOL

Lawrence Livermore National Laboratory researchers use multiphysics simulation to develop techniques to repair fused silica optics

Lawrence Livermore National Laboratory (LLNL) needed to repair and recycle fused silica optics damaged by repeated exposure to the high‑power beams of the National Ignition Facility (NIF). To understand complex laser–material interactions and develop reliable repair methods for the system’s tens of thousands of optics, LLNL researchers turned to Comsol and its COMSOL Multiphysics software to model the coupled thermal, mechanical, chemical and fluid phenomena involved.

Using Comsol, the team simulated temperature-dependent elastic and viscous flow, evaporation/redeposition, and precursor flow and decomposition to develop and optimize three repair approaches—IR pulsed microshaping (RAM), slow annealing, and laser chemical vapor deposition (L‑CVD). The simulations matched experiments, helped avoid surface rippling and unwanted L‑CVD “volcano” features, and supported process optimization; as a result, over 130,000 damage sites have been repaired through 2014, enabling optics to be recycled back into NIF and extending optic lifetime while reducing processing costs.

Lawrence Livermore National Laboratory

Manyalibo Matthews

Deputy Group Leader