Researchers like Dr. Rami Kalyanaraman and Gerd Duscher, associate professors of materials science engineering at the University of Tennessee, could not develop cloaking devices or work to achieve true invisibility without the use of metamaterials. But what are these fancy new materials and how do they work?
Defining Metamaterials
Metamaterials are a fairly new class of human-made materials engineered to produce properties that do not occur naturally. The way naturally-occurring matter behaves is dependent on the molecules it contains. In other words, the properties an element will have – ability to reflect light, for example – are determined at the atomic level.
Researchers use these new metamaterials to control and manipulate light and sound, among other physical properties of a structure.
How Do They Work?
In the world of metamaterials, the way a material behaves is completely dependent on the way certain elements are constructed. At UT, Kalyanaraman and Duscher experimented with silver and cobalt and discovered that when these two elements were coupled, they exhibited strong optical and magnetic properties, which contribute to the ongoing research in cloaking devices.
All natural matter reflects and refracts light, which is electromagnetic radiation made up of electric and magnetic fields. The amount of light reflected by an object depends on how the electromagnetic waves of the light interact with the particles on an atomic level.
Metamaterials affect the magnetic component of light. Because of this, the range of potential interactions with light expands. When used in cloaking, these metamaterials bend the electromagnetic radiation (the light) around the object, which produces the invisibility effect.
Metamaterials guide light around an object instead of reflecting the light or refracting it like naturally-occurring materials.
Another way to think about how this works is to imagine a piece of woven fabric like a shirt or sheet with a high-quality thread count. As light travels across the fabric, it stays in the lanes of the fabric and only flows over the threads.
If a hole is punched into that piece of fabric, the light will travel around it because it can only travel on the thread. To the light waves, the hole does not exist. If an object appears in the hole, the light would travel around the object, basically making it invisible.
Future of Metamaterials
Invisibility as a concept has intrigued humans for centuries, but it was only over the past decade that researchers realized cloaking devices were no longer just a theme in the science fiction world. It was becoming a reality.
Now, researchers across the globe are studying how to create metamaterials with optical properties in order to achieve invisibility.
However, there is more to the world of metamaterials than re-creating Harry Potter’s cloak of invisibility. Any tool or piece of technology based on the interaction of electromagnetic waves with objects has the potential to be enhanced using metamaterials.
Increased computing power is an area where metamaterials could drastically improve the capacity for storage and processing of information. Other examples include MRI machines, radios and any communication devices that use magnetism and light to share information.
Advances in cancer treatments are also possible with the use of metamaterials. If doctors are able to see the specific cancers cells or growths, they can use targeted radiation or pharmaceutical methods to kill the cancer cells.
The world of metamaterials research is still very young, but with researchers like Kalyanaraman and Duscher, the technological hurdles will soon yield to scientific breakthroughs that will change the way we interact with our natural world.