They seam to have a flatness of λ/2 - λ/4 and are quite cheap, 10 bucks for a 25mm diameter one (that 1/5 the price of a normal 25mm secondary elliptical mirror)

  • CanadaPlus@lemmy.sdf.orgEnglish
    3·
    14 days ago

    Are you sure flatness is measured the same way as you’re used to? For a resonant cavity I’d expect total surface shape is not as important as it would be for something image-forming.

    I mean, it could be. You can lapp something flat pretty easily. I’d consider it, though.