3 ms·

Which mirrors are that, and why are they made, what are they used for? Just giant telescopes on remote mountaintops, or is there more?

• buran77 6y ago
  Lasers! :) I'm talking about dielectric mirrors. Wikipedia suggests 99.999% or better reflectivity over a narrow range of wavelengths.
  • Arnt 6y ago
    Of course. Duh.