This really, really, really, depends on the grade of the Quartz. Gas laser Brewster windows used by Coherent, Melles, and Lexel are "Swept" Quartz or Fused Silica where a electric field is applied to Quartz at a high temperature to "pull" impurities to one side through electro-migration. The quartz is then checked with a HENE for scattering centers prior to polishing... Needless to say this is not cheap..
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An AR coated, Swept Quartz or Superasil window would be ideal and very low loss...
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Oh wait, I misread that... You want the natural diffraction losses from a short plano-plano cavity.. You need Kolgelnik's (spelling?) work on laser cavity modes and optics. I'll dig it up. Probably Dr. Anthony Siegman's book on laser cavities as well...
Steve
Last edited by mixedgas; 02-04-2016 at 09:07.
Qui habet Christos, habet Vitam!
I should have rented the space under my name for advertising.
When I still could have...