This site uses cookies. By continuing to use this site you agree to our use of cookies. To find out more, see our Privacy and Cookies policy.
Skip to the content

Share this

Free weekly newswire

Sign up to receive all our latest news direct to your inbox.

Physics on film

100 Second Science Your scientific questions answered simply by specialists in less than 100 seconds.

Watch now

Bright Recruits

At all stages of your career – whether you're an undergraduate, graduate, researcher or industry professional – can help find the job for you.

Find your perfect job

Physics connect

Are you looking for a supplier? Physics Connect lists thousands of scientific companies, businesses, non-profit organizations, institutions and experts worldwide.

Start your search today


Space–time cloak becomes reality

By Hamish Johnston

In this month’s issue of Physics World, Martin McCall and Paul Kinsler outline plans for an “event cloak” – a device that would be perfect for the ultimate bank heist. Now, physicists in the US are the first to build one.

McCall and Kinsler are theoretical physicists at Imperial College London and their article offers a recipe for a device that allows selected events to go undetected.

Now it seems that Alexander Gaeta and colleagues at Cornell University have built a working event cloak – albeit different from the McCall and Kinsler’s proposal.

The device comprises two “split time lenses” (STLs). The first STL takes a beam of light and splits it into two parts, one that is delayed in time and the other that is advanced in time. This creates a gap in time and any event occurring within this gap cannot be detected by the beam. The second STL then does the reverse on the beam, closing the gap in time.

An easy way of understanding this process is the “stream of cars” analogy in McCall and Kinsler’s article.

Indeed, McCall told “We were very pleased to see that our concept has been realized experimentally – it doesn’t quite use the same technique we proposed, but I think it can fairly claim to be the first experimental observation of the signature of a space–time cloak”.

The July issue of Physics World is devoted to the physics of invisibility and you can download a free PDF copy here.

A paper describing the cloak has been uploaded to the arXiv preprint server and the authors say it will be published in Nature. The latter means that Gaeta and colleagues are unable to speak about the paper.

This entry was posted in General. Bookmark the permalink.
View all posts by this author  | View this author's profile

Comments are closed.


  • Comments should be relevant to the article and not be used to promote your own work, products or services.
  • Please keep your comments brief (we recommend a maximum of 250 words).
  • We reserve the right to remove excessively long, inappropriate or offensive entries.

Show/hide formatting guidelines

Tag Description Example Output
<a> Hyperlink <a href="">google</a> google
<abbr> Abbreviation <abbr title="World Health Organisation" >WHO</abbr> WHO
<acronym> Acronym <acronym title="as soon as possible">ASAP</acronym> ASAP
<b> Bold <b>Some text</b> Some text
<blockquote> Quoted from another source <blockquote cite="">IOP</blockquote>
<cite> Cite <cite>Diagram 1</cite> Diagram 1
<del> Deleted text From this line<del datetime="2012-12-17"> this text was deleted</del> From this line this text was deleted
<em> Emphasized text In this line<em> this text was emphasised</em> In this line this text was emphasised
<i> Italic <i>Some text</i> Some text
<q> Quotation WWF goal is to build a future <q cite="">
where people live in harmony with nature and animals</q>
WWF goal is to build a future
where people live in harmony with nature and animals
<strike> Strike text <strike>Some text</strike> Some text
<strong> Stronger emphasis of text <strong>Some text</strong> Some text