Optical-grade silicon is a high-purity, single-crystal form of silicon (Si) specifically manufactured for infrared (IR) optical applications. While standard semiconductor-grade silicon is used in electronics, optical-grade silicon is refined and processed to meet stringent optical requirements—particularly in terms of purity, crystal quality, and low absorption in the IR spectrum. This material is transparent from approximately 1.2 µm to 7 µm, making it ideal for use in mid-infrared (MIR) optics such as lenses, windows, beam splitters, and IR sensors.