Large-area conditioning of optics for high-power laser systems
In order to reach the high fluence goals of the Beamlet laser at Lawrence Livermore National Laboratory (LLNL), the polarizers in the system must be laser conditioned to increase their damage thresholds. Research has shown that by using a six-step raster-conditioning program, the damage thresholds of the HfO{sub 2}/SiO{sub 2} multilayer polarizer coatings can be increased to meet the Beamlet 3-ns design goal of 8 J/cm{sub 2}. Because of the large size of the polarizers (73 cm {times} 37 cm {times} 9 cm), a large-area conditioning facility was constructed capable of rastering a one-meter optic, weighing as much as 400 pounds, at any specified use angle. A large translational stage moves the optic in a raster pattern through a stationary, 10-Hz rep-rated, 1064-nm beam with 10-ns pulses. A scatter measurement diagnostic allows on-the-fly evaluation of laser-induced damage and logs the coordinates of the damage. Laser energy is measured pulse-to-pulse in order to ensure stability during a scan. A small amount of minor coating damage does occur during the process, but the damage does not grow upon further irradiation. This damage causes only a small increase in total scatter compared to that due to the preexisting defects, and would not influence the system performance.
- Research Organization:
- Lawrence Livermore National Lab., CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 10125939
- Report Number(s):
- UCRL-JC-114998; CONF-931054-8; ON: DE94007028; TRN: 94:003640
- Resource Relation:
- Conference: 25. Boulder damage symposium: annual symposium on optical materials for high-power lasers,Boulder, CO (United States),27-29 Oct 1993; Other Information: PBD: 21 Dec 1993
- Country of Publication:
- United States
- Language:
- English
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