Application of germanium in infrared optics industry

Metal germanium has excellent infrared optical properties and physical properties. It is an ideal window, lens and drum material for thermal imaging cameras. It is widely used in night vision and thermal imaging cameras for reconnaissance and warning. It has great advantages in the field of infrared optics. irreplaceable position. At present, the infrared optics industry has become the largest application market of germanium, accounting for about 42% of the total consumption of germanium.

Germanium is a rare and scattered metal with a loose distribution. At present, China's reserves and output of germanium metal rank among the top in the world. As the largest producer of metallic germanium, sufficient raw materials have driven the development of China's germanium industry in the field of infrared optics. However, at present, the germanium industry is still in the stage of supplying primary materials. With the adjustment of national policies, my country's germanium research and development and application will make leaps and bounds. In-depth technical cooperation among germanium companies will further deepen, and the germanium industry and infrared optics industry will also further develop and grow.

Infrared optical properties of germanium materials

With the rapid development of laser and infrared technology, the excellent properties of semiconductor materials represented by germanium in infrared optics have attracted increasing attention.

Infrared optical materials need to have the following characteristics:
(1) Broad infrared transmission band;
(2) High transmittance for infrared rays of different wavelengths;
(3) Ideal refractive index and low dispersion for infrared rays of different wavelengths;
(4) The material has good mechanical and thermal properties and adaptability to the environment;
(5) Easy to process into various shapes and large sizes;
(6) Low manufacturing cost.

At present, the main infrared optical materials include semiconductor materials germanium and silicon, as well as III-IV compound semiconductors GaAs (gallium arsenide), GaP (gallium phosphide) and IIIII compound semiconductors ZnS (zinc sulfide), ZnSe (selenium Zinc), etc.

In infrared detection systems such as infrared thermal imaging cameras, germanium is most widely used as windows and lenses, prisms and filters. Germanium has the highest refractive index and is easy to process into lenses. It has good transmittance in the 8-14 μm band (up to more than 95% after coating); germanium is corrosion-resistant, not easy to deliquesce, and has good mechanical properties. In infrared detection systems, germanium is an irreplaceable material.

Application of germanium materials in the field of infrared optics

In infrared optics, germanium is mainly used to make infrared optical lenses in infrared detection systems and infrared optical windows to protect infrared optical lenses. More than 60% of the lenses in mid- to low-end infrared optical lenses are made of infrared germanium single crystal materials. In high-end infrared optical systems, half of the optical lenses are germanium single crystals.

Infrared lenses are mainly used in both military and civilian applications. The main application areas of military infrared lenses include airborne infrared lenses, ship-borne infrared lenses, land-based infrared lenses, vehicle-mounted infrared lenses, infrared gun sight lenses, helmet infrared lenses, handheld infrared lenses, etc. The main application areas of civilian infrared lenses include security, civilian vehicles, civilian ships, civil aircraft, police, etc.

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