When we speak about film and optics, it’s easy to get confused and think of videography.
However, optically thin film has nothing to do with this. Instead, we’re talking about the thin film coating applied to surfaces to change their reflective properties, and therefore, their optics.
This article will cover everything you need to know about this thin coating and what it can achieve.
Let’s get started!
What’s Optically Thin Film?
Optical thin-film coating modifies the optical characteristic of the surface on which it’s applied. They can influence the reflection, polarization, or transmission properties of an optical component.
There are a few common categories for different applications.
Antireflection: You can apply thin films to materials to make them less reflective. The thin coating can make the surface appear more muted and dull, making it less glaring when confronted with light.
High reflection: Thin mirror coatings make surfaces more reflective.
Partial Reflection: With a coating that modifies glass to partially reflect, you can keep out specific frequencies of light and only let in a percentage of the overall brightness.
You’ll find this useful for buildings in which windows often obstruct your view of screens.
Filters: Optically thin films can act as filters for specific wavelengths of light. For example, they may transmit Infrared or Ultraviolet Light while rejecting the other.
This enables the thin film to have applications in keeping houses better insulated, whether the goal is to keep them heated or keep them cool.
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How’s Optical Coating Constructed?
You can construct optical coatings from thin dielectric layers or thick layers of metals.
We discuss the former with a thin film consisting of oxides, metals, or rare earth materials. The optically thin film performs differently depending on the number of layers of material and the refraction between them.
Common materials include:
- Tantalum pentoxide
- Aluminum oxide
- Hafnium oxide
There are several different coating technologies for applying the optically thin film. The type of application determines the coating’s stress, density, smoothness, process time, and repeatability.
Applications for Optically Thin Film
There’s a wide range of applications for optically thin film, and coatings can be found in a significant number of industries. Furthermore, the scope of these applications is likely to expand as new technologies emerge.
Just to name a few examples, optically thin film coatings can be applied to devices and displays to improve their performance. Thin layers are also commonly used for windows in ordinary homes.
There, they can help keep the heat in or out, or they can darken rooms that are too bright during the day.
As a result, window coatings can play a massive role in keeping energy costs down and making the most of the daylight.
But thin-film coatings also appear in industries such as:
- Photonic devices
- Automotive optics
- Photovoltaics and more
They can also be found in nature, such as on a butterfly’s wing, where layered materials will display vibrant colors.
Wrapping-Up on Thin Film
As you’ve seen, optical coatings are found all around us in a range of products. Furthermore, it’s our belief that applications for this technique are likely to expand in the future.
If you enjoyed this article on thin film, you’ll find similar content over on our blog’s ‘tech’ section. Enjoy!
Rachel Dixon works on travel and features at Daily Mid Time