Experimental investigation of the laser conditioning efficiency by nanosecond pulses at 266 and 355 nm in high reflectivity mirrors used in optical parametric oscillators (OPOs) is present in this report. The high reflection coatings were deposited on the fused silica substrates. The materials used for e-beam coating deposition were ZrO₂ and SiO₂. Laser conditioning was investigated as function of number of pulses, wavelength and conditioning protocol. Ramped-fluence pre-exposure was used as a method to explore optimal improvement to the damage performance at 266 and 355 nm. No conditioning effect was observed using nanosecond pulses at 266 nm, but the mirror conditioning with 355 nm pulses increased the laser-induced damage threshold (LIDT) by 2.5-3 times. The experimental results support the concept that the laser conditioning effect observed in high quality optical thin films is associated with intrinsic electronic defects in the films.

Date Published: 31 December 2009
PDF: 6 pages
Proc. SPIE 7504, Laser-Induced Damage in Optical Materials: 2009, 750408 (31 December 2009); doi: 10.1117/12.836496

Published in SPIE Proceedings Vol. 7504:
Laser-Induced Damage in Optical Materials: 2009
Gregory J. Exarhos; Vitaly E. Gruzdev; Detlev Ristau; M. J. Soileau; Christopher J. Stolz, Editor(s)