Investigation of Contamination Effects on Laser Induced Optical Damage in Space Flight Lasers

Molecular and particulate contamination within laser systems represent two of the largest risks associated with laser systems. Optical design typically minimizes the risk due to strictly optical intensity damage related issues. However, the presence of contamination in the laser system can negate the designed in safety margins, resulting in optical damage under conditions where it would not normally occur. NASA has adopted risk management as a universal goal, to manage risk, one must know what it is. This requires a fundamental understanding of the principle processes. There have been about ten papers published in the area of molecular contamination induced laser optical damage.[1-14] These papers have primarily been investigations into single events and have not provided significant insight into the behavior that can be expected in other cases. This is expected, as the current state of laser induced optical damage is not understood at the materials level. Without the knowledge of the changes in the optical materials during laser damage events, understanding the contributions of outside materials in combination with the optical materials is beyond hope. This project investigated the contamination effects on the laser optical damage process both at a theoretical level and through laboratory measurements. A numerical modeling paradigm has been developed for the interaction of laser beam intensity and matter at the atomic and molecular level. Measurements have been made that provide heretofore-unseen behavior in laser optics that provides significant insight into the behavior of laser damaged optics.