Thermal imaging investigation of modified fused silica at surface damage sites for understanding the underlying mechanisms of damage growth
We use an infrared thermal imaging system in combination with a fluorescence microscope to map the dynamics of the local surface temperature and fluorescence intensity under cw, UV excitation of laser-modified fused silica within a damage site. Based on a thermal diffusion model, we estimate the energy deposited via linear absorption mechanisms and derive the linear absorption coefficient of the modified material. The results indicate that the damage growth mechanism is not entirely based on linear absorption. Specifically, the absorption cross-section derived above would prove insufficient to cause a significant increase in the temperature of the modified material under nanosecond, pulsed excitation (via linear absorption at ICF laser fluences). In addition, irreversible changes in the absorption cross-section following extended cw, UV laser exposure were observed.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 896608
- Report Number(s):
- UCRL-PROC-225830; TRN: US200703%%861
- Resource Relation:
- Journal Volume: 6403; Conference: Presented at: Boulder Damage Symposium, Boulder, CO, United States, Sep 25 - Sep 27, 2006
- Country of Publication:
- United States
- Language:
- English
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