Silicon is commonly used as substrate material for infrared reflectors and windows in the 1.5 - 8 micron region. The strong absorption band at 9 microns makes it unsuitable for CO2 laser transmission applications, but it is frequently used for laser mirrors because of its high thermal conductivity and low density. Silicon is also useful as a transmitter in the 20 micron range. Maximum available size:100 mm Dia x 50 mm Thk.