Silicon (Si) single crystal is a chemically inert material with high hardness and insolubility in water. It exhibits excellent light transmission in the 1-7 μm wavelength range, as well as in the far-infrared band of 300-300 μm, a characteristic not found in other infrared optical materials. Silicon (Si) single crystal is commonly used as a substrate for 3-5 μm mid-wave infrared optical windows and optical filters. Due to its good thermal conductivity and low density, it is also a frequently used material for manufacturing laser mirrors, infrared temperature measurement devices, and infrared optical lenses. The products can be coated or uncoated;