Graphene is a sheet of carbon which is one atom thick. At the University of Central Florida they are working to improve the light absorption of this material. Graphene doesn’t do well at absorbing light, it absorbs about 2%.
Initially they tried to embed metal particles in the fabric but this did not improve the absorption rate. They came upon the idea of altering the shape of the material but not the composition of the material itself. They stamped a pattern onto the material creating an optical cavity. This cavity acted as something similar to an ‘infinity mirror’.
An infinity mirror is made by setting up two mirror facing each other. This has the effect of an image or in this case a beam of light striking on mirror and reflected to the opposite mirror. The opposite mirror will in turn reflect the beam back towards the first mirror. This results in the beam bouncing back and forth between the mirrors, thus the name, infinity mirror. As a side note, this is what happens in a diamond and is the reason a diamond sparkles. If you are interested, leave a comment and I will do a post on how diamonds sparkle.
With this optical cavity, the material was able to extract more of the light’s energy because instead of hitting the material once, it hit the material many times so the 2% absorption rate multiplied by the times the light beam hit it.
The new shape increased the absorption rate by more than 45% but they expect with further adjustments they can get the absorption rate up to about 90%. They also believe that with this technique they can adjust the frequency of light that is absorbed, also known as tunable.
This is an important discovery. This means you have the ability to filter out the wavelengths of light you don’t want to view. Just as an example, you can set it up to see only infrared light, this would make it usable as in a night vision scope. This is just one example because it can be use for a myriad of applications.