Contamination of Optical Surfaces

Abstract

Contamination of optical surfaces is omnipresent in laser systems which are operated under vacuum conditions. In the past, several space-based laser missions have suffered from anomalous performance loss or even failure after short operation times which could be traced back to laser induced contamination. The contamination mechanism consists of deposition, chemical conversion under laser illumination followed by carbonisation, which primarily results in a loss of optical transmission. Even ultrathin layers of hydrocarbons of a few nanometers can induce transmission losses on the percentage level. In this contribution, the aspects of laser induced contamination are discussed.