Custom Silicon

Additional Information

• Silicon can be produced via different methods—most notably the Czochralski (Cz) and Float-Zone (Fz) techniques. When grown by the Czochralski pulling technique, there is an absorption peak at 9µm due to the presence of oxygen, but this is vastly reduced when prepared by the Float-Zone technique.
• Optical grade silicon is usually doped with either boron (p-type) or phosphorous (n-type) to increase its resistivity (5 to 40 ohm cm).
• Like germanium, silicon is a semiconducting material with an indirect bandgap at 1.1µm at room temperature.
• Silicon’s transmission is at around 50% between 1-6µm, and above 50µm, therefore an AR coating is recommended to achieve higher transmission, and a DLC coating can be applied to an exposed surface to increase its durability.

Typical Applications

Thermal imaging

• Silicon windows and lenses are often used for NIR and MWIR thermal imaging applications. Though the image quality may not be as superior as germanium and zinc selenide, silicon does provide a more lightweight and cost effective solution.

Laser Mirrors

• Due to silicon’s high thermal capacity it is an ideal substrate for reflectors used in applications such as CO₂ laser cutters.

FTIR Spectroscopy

• Silicon is often used as the substrate for infrared optical filters that are incorporated into FTIR spectrometers.

IR Detectors

• Silicon optics are often used in NIR and MWIR detectors due to its transmission from 1 to 6µm. Silicon based detectors are used in applications such as LiDAR and muzzle flash detection.