[Video] Invisibility cloak is a mirage

This is a beautiful demonstration of a trick of the light that we are all quite familiar with, and it even has an on/off switch. An aerogel sheet of carbon nanotubes is rapidly heated by electrical stimulation. The heat is conducted away and into the surrounding water, where a mirage effect is created. Light is then deflected away from the layer of heated water, rendering anything placed behind it invisible.

Many novel applications could come from this research into the phenomenon of photothermal deflection. The authors of the paper^† suggest it could be of interest for loudspeaker technology and sonar projectors, but I can imagine some pretty cool magic tricks being made of this.