Cathodoluminescence Microanalysis of the Distribution of defects induced in fused silica by UV laser pulses and after damage mitigation treatment with a CO2 laser
Point defects are induced in high quality optical-grade fused silica by high fluence (>30 J/cm{sup 2}) 355nm laser pulses. The microscopic depth distribution of laser irradiation induced defects has been nondestructively determined using Cathodoluminescence (CL) microanalysis. CL emissions have been observed at 1.9eV, 2.2eV, 2.7eV and 4.4eV. In addition following CO{sup 2} laser treatment for damage mitigation an emission at 3.2eV is also observed. The CL emissions have been identified with the NBOHC (non-bridging oxygen hole center), the STE (self-trapped exciton), an ODC (oxygen-deficient center) and an aluminum impurity centre. The spatially resolved CL data is consistent with damage initiation at the exit surface. The concentration of 355 nm laser induced defects is greatest at the surface and monotonically decays to pre-irradiation levels at {approx}10 {micro}m depth below the surface. With CO{sup 2} processing to mitigate damage, the defect concentration and spatial distribution is reduced to a maximum depth of {approx}6{micro}m. CL microanalysis provides a sensitive and nondestructive method of assessing the magnitude and submicron distribution of irradiation induced damage in technologically important materials.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 15016558
- Report Number(s):
- UCRL-JRNL-204432; JAPIAU; TRN: US200515%%113
- Journal Information:
- Journal of Applied Physics, Vol. 97; Other Information: Journal publication date May 15, 2005; PDF-FILE: 27 ; SIZE: 80.6 KBYTES; PBD: 10 Mar 2004; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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