Video: Cloaking Device Makes a Cat Disappear

Scientists in Singapore and China have crafted a cloaking device that works in natural light, and they’ve recorded videos of a cat and fish disappearing inside it.
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We wish to inform you that we have disappeared your cat. And your fish.

Scientists in Singapore and China have crafted a cloaking device that works in natural light, and they’ve recorded videos of animals disappearing inside it. You wouldn’t want to wear it, though. The cloak is made from thin sheets of glass, and it doesn’t work from all angles.

This new device, described June 7 in a manuscript uploaded to arXiv.org, works by redirecting light waves around objects inside it. But unlike other recently described cloaking devices built from metamaterials — artificial materials with properties not found in nature — it’s made from a type of ordinary glass that bends and disperses light. Scientists reasoned that since human eyes cannot perceive light phase or polarization, it should be possible to achieve a cloaking effect without needing to keep redirected light waves in phase, which has been a challenge for other forms of cloaking.

Instead, ordinary materials arranged in clever ways should do the trick.

First, the team placed six thin pieces of glass inside a hollow, transparent hexagonal chamber. The result is a device with six-fold radial symmetry that will cloak an object from six different directions. To demonstrate its effectiveness, the team submerged the cloak in an aquarium — and watched as a goldfish disappeared as it swam through it while plants in the background remained visible.

Next, the team built a larger version of the device that could hide a cat. Unlike the hexagonal device, this cloak only shields an object from viewers directly in front of or behind it, as evidenced by bits of the curious cat disappearing while inside. Like the fish experiment, the cloak didn’t obscure the background, which in this case was a flowery scene projected onto the wall.

The cloak isn’t ready for prime time yet. In both environments — terrestrial and aquatic — the device itself is still partially visible, owing to the shadows it casts on the projected background and the bits of glue joining the glass with the container.

Fortunately, disappearing household pets isn’t the team’s main goal. In their paper, the scientists suggest that reconfiguring the prisms comprising the device could lead to “important security, entertainment, and surveillance applications.”

Videos: Chen et al., Natural Light Cloaking for Aquatic and Terrestrial Creatures, posted to arXiv.org.