Optical coating services design optical coatings and apply them to crystal, fiber, glass, metal, or polymer substrates to produce optical components. These coatings reduce reflection both internally and externally, increasing the amount of light that reaches the eye and improving brightness and contrast. There are several basic types of optical coatings. Antireflective coatings produce two reflected waves which totally or partially cancel each other out. They may also produce two reflections that are 180° out of phase. Beamsplitter coatings divide a beam that shines onto a substrate into two or more separate beams. Dielectric coatings consist of layers of quarter-wave film that alternate between a high refractive index and a low refractive index relative to the substrate. Optical coating services can produce dielectric coatings that are specific to a reflected wavelength, or spread over a wide wavelength interval. Filter coatings are used to block a specific range of wavelengths such as infrared (IR) or ultraviolet (UV) light. High-reflector coatings can be used to produce mirrors that reflect more than 99% of the light which falls on them. Indium tin oxide (ITO) coatings consist of alloys that are deposited as a transparent film to produce conductive substrates. Protective coatings are used to limit scratching or damage without altering a substrate’s optical properties. Metal coatings and mirror coatings are also available.
Optical coating services design and apply coatings made from a variety of materials. Examples include aluminum, chromium, copper, fluorine, germanium, gold, nickel, platinum, quartz, rhodium, sapphire, silver, titanium, tungsten, and zirconium. Copper, a moderately hard metal, has an average reflectance of 70% in the visible spectrum. Platinum, a very hard metal, offers excellent chemical resistance and has an average visible reflectance of approximately 60%. Silver has the highest visible reflectance, 98%, of all the common evaporated metals. Protected silver retains the high reflectance of bare silver and also has improved environmental and mechanical stability due to the addition of a protective layer. Fluoride compounds are used in films that optical coating services design for the UV and middle-IR regions. Aluminum oxide, hafnium dioxide, tantalum pentoxide, yttrium oxide, and zirconium oxide are used in optical coatings for the near-UV to IR regions. By contrast, thorium fluoride products are designed for high energy applications that require high damage thresholds. Scandium oxide is used in high-index film layers that are transparent to wavelengths as short as 225 nm.
Optical coating services are located across the United States and around the world. Some companies produce optical coatings for medical, dental, or laboratory applications. Others design products for military or aerospace applications. Optical coating services vary in terms of services offered and may provide design assistance and in-house substrate fabrication. Suppliers may recommend standard products or designed custom materials for specific applications.