As a kind of excellent optical lens, sapphire lenses has good transmittance in the ultraviolet, infrared and visible light bands, which can meet the requirements of multimode composite guidance. At the same time, sapphire lens has excellent mechanical properties, chemical stability, high temperature resistance, high strength and high hardness, which can meet the stringent requirements of hypersonic missiles on the transmission plate.
In terms of preparation, sapphire can produce filters, and then be processed and shaped. The performance of the finished products is the same as that of the filters. Other chips are mainly formed by powder hot die-casting sintering, and their performance is slightly lower than the original ones. Therefore, sapphire filters have become a good choice for medium-wave transmission infrared window chips such as high-speed fighters and missiles in advanced countries.
Sapphire is a very ideal multispectral wide-band window material. Compared with ordinary wide-band window materials, it has many excellent mechanical and optical properties, and is suitable for laser instruments, optoelectronic devices, window materials, etc. The infrared transmittance of the sapphire samples before and after the coating was measured. The infrared transmittance of the coated and uncoated sapphire samples at high temperature and after rain erosion was measured and analyzed. The results showed that the infrared transmittance of the sapphire samples after the coating of sio2 film on the sapphire substrate was significantly improved.
At high temperature, sio2 film still has a good antireflective effect. the average transmittance of the coated sapphire sample is significantly higher than that of the uncoated sapphire sample; After the rain erosion test, the average transmittance loss of the coated sapphire sample is very small, and the infrared transmittance of the coated sapphire is significantly higher than that of the uncoated sapphire.
Performance requirements of infrared window slice:
1. High mechanical strength: the infrared window sheet must have high strength to withstand the decompression load during high-speed movement;
2. Good thermal stability: the infrared window of the head shall be able to withstand the temperature shock caused by aerodynamic heating and height change, and the transmittance and refractive index shall not change significantly with the change of temperature;
3. Good chemical stability: when exposed to the air, the infrared window should be able to prevent the corrosion of salt solution or corrosive gas in the atmosphere, and not easy to deliquescence;
4. High optical transmittance: it must be able to effectively transmit the radiation from ultraviolet to mid-infrared bands;
5. Good optical characteristics, small optical scattering and good refractive index uniformity;
6. It can meet the requirements of large windows.