In optical systems, a mirror plays an important role. It is responsible in redirecting light with the purpose of making an optical system more compact. Optical mirror is quite different from household mirror. Basically, optical mirrors are used I applications where a front-surface mirror is needed. This is because the reflective surface is subject to degradation of the environment even though it is normally placed in an environment that is not exposed to harsh conditions. Hence, providing a durable front-surface mirror, which is clean and stable is one of the essential and crucial part of a mirror technology.
Metal Mirror Coatings
If you are looking for the most common and yet the simplest form of mirror coating, then metal mirror coatings are certainly the best deal. Technically speaking, what makes a great reflector for the visible spectrum is a 100-nm layer of silver or aluminum. Silver has the ability to reflect about 95 percent of the light across the visible spectrum while aluminum has the ability to reflect 90 percent only. According to experts, silver is considered to be the most reflective visible spectrum. However, Aluminum is usually used in the application of astronomical telescope mirrors, UV applications and others compared to silver.
Other metals like gold and copper are also useful in the IR spectral regions. Generally, shiny metals would suffice situations that have higher durability.
Aluminum is considered to be stable as a mirror but what quickly tarnishes is silver.
All-dielectric mirror coatings
Another coatings for mirror are the dielectric mirror coatings. Mirrors can also be created through depositing a stack of alternate high-and-low index dielectric layers on a glass substrate. If you want to create a mirror for a given light wavelength, the thickness of every layer is selected in order for the product of the thickness and the index of refraction of the layer is supported.
But overall, aluminum and silver are the most common mirror coatings used in different applications. Aluminum has properties that make it one of the most ferrous metals that can be utilized in an array of applications. While aluminum can be weak in its pure form, the process of chemical treating and alloying drastically increase its strength. Aluminum mirrors are commonly used in applications such as optics, aerospace, defense and medicine.
On the other hand, silver mirror coatings are considered ti be low cost substitute for aluminum. It has properties that provide advantage in heat absorption, tensile strength, conductivity and corrosion resistance. This is the reason why silver is also considered as an excellent metal to use for plating and a good alternative for gold plating. For more information, you can visit https://www.evaporatedcoatings.com/optical-mirror-coatings/ to learn more about optical mirror coating. Knowing the best optical mirror coating will certainly help you to use the right materials and component. So whatever application you are working on, whether it is medicine, optics, aeronautics and others, choosing and using the right mirror coating will help you be successful on it.
