Skip to Content

Chinese Researchers Make An Invisibility Cloak In 15 Minutes

Look out for mass-produced invisibility cloaks thanks to an entirely new way of designing and manufacturing them out of materials such as Teflon.

When it comes to invisibility cloaks, one of the trickiest problems is how to make the things.

The materials of choice are known as metamaterials which are created by assembling a repeating pattern of structures that interact with the light they are designed to cloak. This kind of detailed assembly means that making metamaterials is an expensive and time-consuming process. What’s more, the resulting invisibility cloaks are never perfect 

So physicists have begun to wonder if they can do just as well with other materials that are easier and simpler to make.

Their approach is entirely different to the theoretical light-bending mathematics physicists have used until now.  This current approach works by attempting to steer electromagnetic fields around an object in a way that hides it. The necessary material must be able to repeat this kind of light distortion in real life.

The new approach is to create a computer model of the cloak in the form of a conventional material with fixed light bending properties.

The model simulates how this conventional material distorts light as it passes by. The computer then changes the shape and topology of the material to reduce this distortion.

By repeating this process many times, it is possible to find a topology that minimises the distortion of light so that it remains more or less unchanged as it passes by. The result is an invisibility cloak; not a perfect one but one that can hold its own against many of those made of metamaterials.

At least, that’s the theory. So-called topological optimisation has been little more than a twinkling in a few applied physicists’ eyes. Until now.

Today, Lu Lan at Zhejiang University in China and a few pals have actually created the first invisibility cloak designed using topology optimisation. They carved it out of Teflon and it took them all of 15 minutes using a computer-controlled engraving machine. “The fabrication process of a sample is substantially simplified,” they say.

The resulting “Teflon eyelid” invisibility cloak hides a cylindrical disc of metal the size of poker chip from microwaves. But crucially, its performance closely matches the prediction of the computer simulation.

That significant because it brings invisibility cloaks into the realms of mass production. There is no reason why Teflon eyelids couldn’t be printed or moulded en masse.

What’s more, Lu and co so there is no reason why the same approach can work in optical wavelengths. “Such a cloaking setup won’t be a big problem to replicate in the THz or even optical spectrum,” they say.

Of course, there are challenges ahead. Lu and co want to develop the technique to create cloaks that work over a range of frequencies and at a range of angles. If they can make them cheaply and easily for a cost measured in pennies, there’s no reason why invisibility cloaks won’t soon be everyday objects.

Ref: Experimentally Demonstrated An Unidirectional Electromagnetic Cloak Designed By Topology Optimization

Keep Reading

Most Popular

DeepMind’s cofounder: Generative AI is just a phase. What’s next is interactive AI.

“This is a profound moment in the history of technology,” says Mustafa Suleyman.

What to know about this autumn’s covid vaccines

New variants will pose a challenge, but early signs suggest the shots will still boost antibody responses.

Human-plus-AI solutions mitigate security threats

With the right human oversight, emerging technologies like artificial intelligence can help keep business and customer data secure

Next slide, please: A brief history of the corporate presentation

From million-dollar slide shows to Steve Jobs’s introduction of the iPhone, a bit of show business never hurt plain old business.

Stay connected

Illustration by Rose Wong

Get the latest updates from
MIT Technology Review

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

Explore more newsletters

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at with a list of newsletters you’d like to receive.