A brief introduction: optical lens materials
Optical lens is an important part of optical system and an essential knowledge in optical engineering. A lens is an optical element that can be made from a specified spectrum of materials. Generally, optical glass is used for visible light and near-infrared spectroscopy (IR-A)(400-1400nm), and crystalline materials are used for mid-infrared (IR-C)(3-50mm). Lens technology can be widely used in machine vision, digital imaging, direct and focusing of lasers, and various optical instruments.
Optical materials are generally divided into amorphous, crystalline and organic plastics. Different materials have applicable spectral ranges and different physical properties (coefficient of expansion, density, hardness, etc.). Common materials in the amorphous state include optical glass, infrared glass and laser glass. This material has the characteristics of mature manufacturing process and complete specifications. Among them, colorless optical glass is mainly a composite product based on SiO2 and mixed with other elements, mainly used in 400-100 coronal N optical band. The main characteristics of other glasses are that they have a certain refractive index and dispersion. Internationally, according to these two parameters, they are basically divided into optical glass (K) and flint optical glass (F). Coronal optical glass has low refractive index and large Abbe number. Flint optical glass has high refractive index and low Abbe number.
K9 (SCHOTT corresponds to BK7) glass is a common glass in general scientific research. Its performance is moderate, the material processing performance is good, the price is relatively cheap. Therefore, it is the first choice for single-mirror applications and the base material for many coating components. The other is fused quartz JGS1 (CORNING corresponds to 7980). Because of its good stability and small thermal expansion coefficient, the material is widely used in high-power lasers, but its price is also relatively expensive, especially when the size is very large.
