Optimization of Laser-Damage Resistance of Evaporated Hafnia Films at 351 nm

Journal Article · Tue Apr 07 04:00:00 EDT 2009 · Laser-Induced Damage in Optical Materials: 2008

OSTI ID:950855

Oliver, J B ^[1]; Papernov, S; Schmid, A W; Lambropoulos, J C

---

1. Laboratory for Laser Energetics, University of Rochester, Rochester, NY

A systematic study was undertaken to improve the laser-damage resistance of multilayer high-reflector coatings for use at 351 nm on the OMEGA EP Laser System. A series of hafnium dioxide monolayer films deposited by electron-beam evaporation with varying deposition rates and oxygen backfill pressures were studied using transmission electron microscopy (TEM), x-ray diffraction (XRD), and refractive index modeling. These exhibit microstructural changes for sufficiently slow deposition rates and high oxygen backfill pressures, resulting in an absence of crystalline inclusions and a lower refractive index. Hafnia monolayers exhibited laser-damage resistance as high as 12 J/cm^2 at 351 nm with a 0.5-ns pulse. This process was utilized in the fabrication of reduced electric-field-type multilayer high-reflector coatings. Measured laser-damage thresholds as high as 16.63 J/cm^2 were achieved under identical test conditions, an exceptional improvement relative to historical damage thresholds of the order of 3 to 5 J/cm^2.

• Research Organization: Laboratory for Laser Energetics, University of Rochester
• Sponsoring Organization: USDOE
• DOE Contract Number: FC52-08NA28302
• OSTI ID: 950855
• Report Number(s): DOE/NA/28302-881; 2008-74; 1859
• Journal Information: Laser-Induced Damage in Optical Materials: 2008, Journal Name: Laser-Induced Damage in Optical Materials: 2008 Vol. 7132
• Country of Publication: United States
• Language: English

Related Subjects

hafnia
laser damage
nanocluster
thin film