The 10QM20HB.31 High-Energy Nd:YAG Harmonic Beamsplitter is 1.0 in. (25.4 mm) in diameter with high reflectivity at 266 nm, and high transmission at 1064 nm. The back surface is AR coated for 532 and 1064 nm. Our harmonic beam splitters are designed to separate Nd:YAG laser harmonics after frequency multiplication. These 25.4 mm diameter optics are precision polished select grade fused silica coated with hard refractory multilayers for high damage threshold. Harmonic beamsplitters are sometimes called Dichroic Filters or Beam Combiners.