Optical window is transparent and flat, that allows light into an optical instrument. Optical windows are applied for protecting fragile optical components inside an equipment from environment conditions.
Optical Windows are available in a wide variety of substrates, such as N-BK7, Fused Silica, Sapphire, Silicon, ZnSe, CaF2 etc.
And Pandas Optics offer different shape optical window ,like square, round, strip, ellipse etc.