Recent Progress in Understanding Fundamental Mechanisms of Laser Induced Damage in Optical Polymers
SourceDamage studies in polymers of acrylic and methacrylic type with low-molecular additives like water, alcohols, and similar compounds are presented. It was established that some additives significantly (by a factor of 10 to 100) increases multi-shot laser damage resistance of polymers. Vibration energy transfer (vibrational cross-relaxation) from polymer macromolecule to additive molecules which suppress the laser created absorbing radicals was shown to be attributed to such damage resistance increase. A mechano-chemical mechanism of laser damage in polymers is proposed which includes laser excitation of vibration states and creation of absorbing “hot radicals”. Basing on this mechanism we proposed methods of physical modification of polymers with high laser damage resistance comparable with that of silicate glasses and crystals.