Hidden Secrets: Invisibility

Ever thought that you could just disappear? Whether being in a really embarrassing situation or just wanting to have an invisibility cloak like Harry Potter and go around sneaking into the library on friday night, we have got to admit that being hidden in plain sight would be pretty incredible.  But, the question to do that, is how?

harry potter invisibility cloak

Harry Potter’s Invisibility cloak

 One of the most promising and recent developments in invisibility, is a new exotic material called metamaterials.  Metamaterials, are artificially engineered materials that have materials not found in nature, and that are arranged in exacting structures using different materials such as different plastics and metals.  Based upon their exact shape, they could be used to affect the waves of sound and, in this case, light in an unconventional manner.  In 2006 at at Duke University in Durham North Carolina, there was a recent breakthrough in which they they were able to use metamaterials to make an object invisible to microwave radiation.  This metamaterial was created by embedding tiny electrical circuits within copper bands that are arranged in flat concentric circles, which resemble coils of an electric oven, and makes it possible to bend and channel the path of microwave radiation.  By being able to bend and channel the path of microwave radiation in specific ways, it resulted in the “invisibility” of the object.

How do metamaterials work

Despite being able to bend the microwaves to render the object invisible, scientists still have to work on the reflection and shadows of the object.  The key to metamaterials, is having a negative index of refraction.  First of all, the speed of light in a vacuum is faster than the speed of light in glass or water, since the light passes through trillions of atoms and that is why it slows down.  And, the Index of Refraction is the speed of light divided by the slower speed of light inside the medium.  For example, since light slows down in glass, it’s index of refraction is always greater than 1.0, and in this case, it is 1.5.  Now, if if you could control the index of refraction inside a metamaterial at will, so that it could change continuously at every point, then as the light moves through a material it could bend in new directions and the light could pass around an object.  And, to do this we must have a negative index of refraction, which practically every optics textbook has said is impossible.  However, despite all of these beliefs, physicists have been able to construct metamaterials in a laboratory.

invisibility and metamaterials

A type of invisibility cloak

In the future, it is believed that complete invisibility is achievable, and that someday perhaps we will have an invisibility cloak, exactly like that of Harry Potter.



Michio Kaku’s Physics of the Impossible




  1. Another type of material that can make something “invisible” is ferrofluid. The US Airforce is currently developing a ferrofluid based paint that, when applied to spy planes, renders them invisible to radar.

    • Mulan Ramani says:

      Wow, as I was researching the metamaterials I actually didn’t see anything on that, but that’s pretty amazing! Thank you for letting me know.

  2. Valeriya Zaborska says:

    It’s amazing by how much previous theories are continuously being changed and making the impossible possible. If this research leads to successful results, do you think there are any cons to having materials that make you invisible ? Would this be unsafe to society in some cases ? Regardless, this would be really cool.

    • Mulan Ramani says:

      I guess that as with any new advance in technology, there will always be a few cons that come with it, but I truly believe that metamaterials could help in different parts of people’s lives, on top of making a very interesting game of hide and seek…

  3. Tiffany Chen says:

    Very interesting! I’m definitely buying one of those invisible cloaks when they come out (;
    @Dante Yes! The development process is already done actually, and rumour has it that it’s already in use on some US aircrafts…!

  4. Ooooo, another post about metamaterials, awesome! The topic of metamaterials came up briefly in another blog post; it was nice to hear an in-depth explanation. This is definitely a fascinating research and development topic.

    Your article makes really good use of pop culture references (Harry Potter WOOT), diagrams, and pictures. I think placing the diagram directly below the paragraph that describes it would make it easier for the reader to understand the concepts. Otherwise, great post, keep it up!

    • Mulan Ramani says:

      Thank you for the advice! And I’ll make sure to change the diagram placement, to make it easier for others to understand.

  5. Somaya Amiri says:

    What!! Technology makes me amazed everyday! I can’t believe how people’s imagination will affect technology. I’m pretty sure that Harry Potter’s invisibilty cloak had a huge impact on this discovery. I really need a cloak to hide myself when I’m late… I’ll sneak in class and seat in my seat and take off my cloak and when teacher asked where I was I would say she is bline 😛

  6. I wonder how people might apply this technology…

    • Mulan Ramani says:

      I know! There are unlimited posibilities to this technology, and I can only imagine the future of it and how amazing it would be!