By WDQ OPTICS | 20 May 2022 | 0 Comments
Introduction to infrared optical materials
Introduction to infrared optical materials
Infrared optical materials refer to a class of materials used in guidance technology and infrared imaging to manufacture filters, lenses, prisms, window sheets, fairing, etc. These materials have physical and chemical properties to meet the needs, that is, the main indicators are: good infrared transmittance and wide projection band. In general, the transmittance and transmission of infrared optical materials are closely related to the internal structure of materials, especially the chemical bond and energy level structure. For example, for crystal materials, the short wave absorption limit mainly depends on the band gap, while the long wave limit mainly depends on the phonon absorption, that is, the lattice vibration absorption. The frequency t of lattice vibration is related to the absorption long wave limit, that is, the lower the vibration frequency t, the greater the long wave limit. For diamond crystal materials, there are strong primary lattice vibration harmonics and weak subharmonic absorption in the infrared band, Therefore, diamond structure crystal has better light transmittance and wider frequency band characteristics.
For crystal materials, the infrared transparency of most single crystal materials is almost the same as that of polycrystalline materials without considering the library and defects (porosity, etc.). Because the properties of polycrystalline materials are the same as those of single crystals, and there is no solid solution inside, their mechanical strength, thermal shock resistance, and economy have been greatly improved. Because it is single crystal, it can achieve large size. In some fields, it has replaced single crystal materials.
The projected band and transmittance of glass and plastics are related to the atomic and molecular structures. However, due to the long-term disorder of their structures, the relationship between their short and long wave absorption limits and the band gap and phonon absorption is relatively vague. The application and research of glass and plastics is an active field in recent years. Today, infrared materials have developed into a large family, and their technologies are complex and dazzling. This paper only introduces the application and development of several important infrared materials in recent years.
Crystal material
Crystal materials are the first infrared optical materials used by people, and are also the main optical materials currently used. Crystal materials include ionic crystals and semiconductor crystals. Ionic crystals include alkali metal halide compound crystals, alkali earth metals, halide compound crystals, oxygenates and some inorganic salt crystals. Semiconductor crystals include o group, o group compounds and o group compound crystals of nitrogen element crystals. Ionic crystals usually have high transmittance and low refractive index, so the reflection loss is small. Generally, anti-reflection film is not required. At the same time, compared with non-ionic crystals, the optical properties of ionic crystals are less affected by temperature. This crystal has a variety of physical and chemical properties, which can meet the needs of different applications. Some crystals also have optical technology, magneto-optic effect, acoustooptic effect, etc. It can be used as detector material.
Infrared optical materials refer to a class of materials used in guidance technology and infrared imaging to manufacture filters, lenses, prisms, window sheets, fairing, etc. These materials have physical and chemical properties to meet the needs, that is, the main indicators are: good infrared transmittance and wide projection band. In general, the transmittance and transmission of infrared optical materials are closely related to the internal structure of materials, especially the chemical bond and energy level structure. For example, for crystal materials, the short wave absorption limit mainly depends on the band gap, while the long wave limit mainly depends on the phonon absorption, that is, the lattice vibration absorption. The frequency t of lattice vibration is related to the absorption long wave limit, that is, the lower the vibration frequency t, the greater the long wave limit. For diamond crystal materials, there are strong primary lattice vibration harmonics and weak subharmonic absorption in the infrared band, Therefore, diamond structure crystal has better light transmittance and wider frequency band characteristics.
For crystal materials, the infrared transparency of most single crystal materials is almost the same as that of polycrystalline materials without considering the library and defects (porosity, etc.). Because the properties of polycrystalline materials are the same as those of single crystals, and there is no solid solution inside, their mechanical strength, thermal shock resistance, and economy have been greatly improved. Because it is single crystal, it can achieve large size. In some fields, it has replaced single crystal materials.
The projected band and transmittance of glass and plastics are related to the atomic and molecular structures. However, due to the long-term disorder of their structures, the relationship between their short and long wave absorption limits and the band gap and phonon absorption is relatively vague. The application and research of glass and plastics is an active field in recent years. Today, infrared materials have developed into a large family, and their technologies are complex and dazzling. This paper only introduces the application and development of several important infrared materials in recent years.
Crystal material
Crystal materials are the first infrared optical materials used by people, and are also the main optical materials currently used. Crystal materials include ionic crystals and semiconductor crystals. Ionic crystals include alkali metal halide compound crystals, alkali earth metals, halide compound crystals, oxygenates and some inorganic salt crystals. Semiconductor crystals include o group, o group compounds and o group compound crystals of nitrogen element crystals. Ionic crystals usually have high transmittance and low refractive index, so the reflection loss is small. Generally, anti-reflection film is not required. At the same time, compared with non-ionic crystals, the optical properties of ionic crystals are less affected by temperature. This crystal has a variety of physical and chemical properties, which can meet the needs of different applications. Some crystals also have optical technology, magneto-optic effect, acoustooptic effect, etc. It can be used as detector material.
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