Limits of performance: CW laser damage

Abstract

High performance optical coatings are an enabling technology for many applications -navigation systems, telecom, fusion, advanced measurement systems of many types as well as directed energy weapons. The results of recent testing of superior optical coatings conducted at high flux levels have been presented. Failure of these coatings was rare. However, induced damage was not expected from simple thermal models relating flux loading to induced temperatures. Clearly, other mechanisms must play a role in the occurrence of laser damage. Contamination is an obvious mechanism-both particulate and molecular. Less obvious are structural defects and the role of induced stresses. These mechanisms are examined through simplified models and finite element analysis. The results of the models are compared to experiment, for induced temperatures and observed stress levels. The role of each mechanism is described and limiting performance is determined.

Continuous-wave laser particle conditioning: Thresholds and time scales

“…While these optics, when pristine, can operate at irradiances of multiple MW cm −2 , particle contamination can drastically reduce their damage thresholds [1,2]. Careful contamination control and regular cleaning are the preferred methods to alleviate these problems; however, many situations require operation even when faced with random contaminants.…”

Combined molecular and metallic particulate laser-induced contamination testing: de-risking activity for the LISA space mission

“…However, since the contact of a contaminant with the optics is important e.g. for the thermal conduction path [16], we wanted to preserve the "natural" bond between particle and surface despite of the vertical optics and decided on the following procedure.…”