Thorlabs offers flat windows fabricated from N-BK7, UV Fused Silica (UVFS), Sapphire, Calcium Fluoride, Magnesium Fluoride, Potassium Bromide, Infrasil, Zinc Selenide, Silicon, Germanium, Barium Fluoride, or Polycrystalline CVD Diamond. Our catalog includes UVFS or Infrasil textured antireflective windows, which feature nanostructured surfaces that provide high resistance to laser-induced damage and low average reflectance over broad wavelength ranges. Our laser windows have a wavelength-specific AR coating centered around commonly used laser wavelengths and an optional wedge, while our precision windows are offered with or without a broadband AR coating. For more information on these substrates, please visit our Optical Substrates page.