Methods for Mitigating Growth of Laser-Initiated Surface Damage on DKDP Optics at 351nm

Conference · Fri Oct 11 04:00:00 EDT 2002

OSTI ID:15002263

Hrubesh, L W; Brusasco, R B; Grundler, W; Norton, M A; Donohue, E E; Molander, W A; Thompson, S L; Strodtbeck, S R; Whitman, P K; Shirk, M D; Wegner, P J; Nostrand, M C; Burnham, A K

We report an experimental investigation of mitigating surface damage growth at 351nm for machine-finished DKDP optics. The objective was to determine which methods could be applied to pre-initiated or retrieved-from-service optics, in order to stop further damage growth for large aperture DKDP optics used in high-peak-power laser applications. The test results, and the evaluation thereof, are presented for several mitigation methods applied to DKDP surface damage. The mitigation methods tested were CW-CO{sub 2} laser processing, aqueous wet-etching, short-pulse laser ablation, and micro-machining. We found that micro-machining, using a single crystal diamond tool to completely remove the damage pit, produces the most consistent results to halt the growth of surface damage on DKDP. We obtained the successful mitigation of laser-initiated surface damage sites as large as 0.14mm diameter, for up to 1000 shots at 351nm and fluences in the range of 2 to 13J/cm{sup 2}, {approx} 11ns pulse length. Data obtained to-date indicates that micro-machining is the preferred method to process large-aperture optics.

• Research Organization: Lawrence Livermore National Lab., CA (US)
• Sponsoring Organization: US Department of Energy (US)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 15002263
• Report Number(s): UCRL-JC-148497
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
ABLATION
APERTURES
DIAMONDS
EVALUATION
LASERS
MITIGATION
MONOCRYSTALS
OPTICS
PROCESSING