Optical coating is an important optical component, which plays an irreplaceable role in the transmission, modulation, and energy division of light. The most basic functions of optical coatings are reflection, antireflection, and spectral control. Optical coatings can bend the light beam to different directions in space according to different requirements and the energy loss of the light beam on the surface or interface is reduced, which can perfectly realize the design functions of modern optical instruments and optical systems. Moreover, depending on the function of spectral control, the chromaticity transformation in optical system can be realized.
Optical coatings can be used as the function elements of polarization, phase, and photoelectricity controlling in the optical system. Taking advantage of unique functions, optical coatings have been fully applied in modern optical technologies such as laser technology, optoelectronic technology, optical communication technology, optical display technology, and optical storage technology.
- Optical instruments field: The lenses of many optical instruments are coated with optical coatings, which can change the light transmittance. Optical coatings in lens can not only improve the imaging quality of the telescope, but also enhance the applicability of the telescope to various environments. For example, when the reflected light is too strong, the imaging color of the telescope will become dim and distorted. Coating the telescope with red film will solve these problems.
- Lighting equipment field: Optical coatings are widely used in lighting equipment, such as incandescent lamp and low pressure sodium lamp, which can make the lighting equipment more energy saving. In general, an infrared light reflection layer is coated on the surface of the lamp to enhance the reflected light and reduce the transmission light. Therefore, the visible light transmission is enhanced.
- Agricultural production facilities field: Optical coatings can be used not only in optical systems, but also in other fields, such as agriculture. Light plays an important role in agricultural production. With the development of science and technology, many agricultural crops are not as dependent on the weather and seasons as they used to be. Many fruits and vegetables are grown in greenhouses and optical coatings are absolutely necessary in this field.
- Antireflection optical coatings: Antireflection optical coatings are the most widely used optical coatings that can reduce the reflectivity of optical surface and improve the transmittance. For single wavelength, the theoretical reflectivity can be reduced to zero and the transmittance is 100%.
- High-reflectivity optical coatings: High-reflectivity optical coatings can reflect back most of the incident light energy. Due to the extremely low energy loss, this kind of high-reflectivity optical coatings are necessary in laser manufacture and laser application.
- Spectroscopic optical coatings: By using spectroscopic optical coatings, part of the incident light energy is transmitted and the other is reflected. For example, spectroscopic optical coatings can divide a beam of light into red, green, blue, and any color that can be obtained by synthesizing the three colors.
- Others: Optical coatings also include energy spectroscopic optical coatings and wide band pass filter optical coatings.