Fracture Induced Sub-Band Absorption as a Precursor to Optical Damage on Fused Silica Surfaces
The optical damage threshold of indentation induced flaws on fused silica surfaces was explored. Mechanical flaws were characterized by laser damaged testing, SEM, optical, and photoluminescence microscopy. Localized polishing, chemical etching, and the control of indentation morphology were used to isolate the structural features which limit optical damage. A thin defect layer on fracture surfaces, including those smaller than the wavelength of visible light, was found to be the dominant source of laser damage initiation during illumination with 355nm, 3ns laser pulses. Little evidence was found that either displaced or densified material or fluence intensification plays a significant role in optical damage at fluences >35J/cm{sup 2}. Elimination of the defect layer was shown to increase the overall damage performance of fused silica optics.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 992760
- Report Number(s):
- LLNL-JRNL-426084; OPLEDP; TRN: US201022%%570
- Journal Information:
- Optics Letters, Vol. 35, Issue 16; ISSN 0146-9592
- Country of Publication:
- United States
- Language:
- English
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