Thin-film optical filters are thin layers of materials with specific optical properties on the surface, such as optical glass. When light is passed through the filters, the path of light changes for each layer, causing internal interference. This is due to the contrast of different components in the dielectric thin film coating. Either reflection, transmission, as well as absorption may occur depending on the wavelength of the incident light and the type of optical filter.
Different Kinds Of Optical Filters
There are various types of thin film optical filters and all kinds of films have a specific purpose.
The anti-reflection film has helped improve transmittance, enhance contrast, and remove ghost images. Because this film is very robust, some anti-reflection film is used for most transmission optical components.
A high-reflective film is a mirror that has been calibrated to maximize reflectivity over a single wavelength or all wavelengths.
This beam splitter film divides light into a plurality of output beams. It is used for projectors, cameras, lasers, etc.
A filter capable of blocking light of a specific wavelength. The thin film reflects, absorbs, and transmits light.
Optical thin films are manufactured for a specific angle of incidence and specific polarizations, such as P-polarization light and s-polarization light. When the optical system changes the incident angle, the internal angle and the optical path length also change, affecting the phase change of the light beams passing through the thin film.
Applications of Thin Film Optical Filters
Thin-film optical filters are highly customizable, permitting them to be designed and manufactured to achieve effective performance in particular light applications. They are used in various industrial fields in various equipment, devices, and systems for various use cases such as the following:
- Biological imaging: They detect biological imaging. Light emission can be filtered to facilitate the operation of the biological image processing device.
- Chemical analysis: They could isolate specific emission, or absorption ranges can be separated from the incident light to assist in the identification and analysis work of the chemical substance.
- Contrast enhancement: They can enhance the contrast between objects during scanning and other image processing to improve identification, recognition, and verification.
- Laser system: The laser system can operate the generated beam.
- Communication system: The signal transmission of the communication system can be separated and changed.
- Coloring of the visible light: The hue of the visible light can be changed to obtain a specific aesthetic effect.
Optical filters are used in a variety of applications because of their flexibility. Applications such as remote sensors, solar imaging, astronomical fluorescence microscopy, Raman spectroscopy, and telecom use optical filters as key components of the equipment are just some applications.