A cloaking device or invisibility cloak has long been featured in science fiction. Attempts have been made to devise a way to do it with objects, but results were disappointing until now. A paper in Nature Communications for September 2013 announces a new approach.[1]
- "Invisibility cloaking was almost inconceivable until the ingenious theory of macroscopic invisibility cloaking was proposed based on transformation optics principles.[2][3] ... We successfully demonstrate the cloaking of living creatures, a cat and a fish, from the eye.[1]
From reference 1, the two "supplementary movies" show the successful cloaking of a goldfish and a cat so far as they are within the experimental space.
Overview
A recent review said these methods were possible: [4][5]
- Optical camouflage: A modified background image is projected onto a cloak of reflective material (the kind used to make projector screens). The wearer becomes invisible to anyone standing at the projection source.
- The "mirage effect": Electric current is passed through submerged carbon nanotubes to create very high local temperatures. This causes light to bounce off them, hiding objects behind.
- Adaptive heat cloaking: A camera records background temperatures, these are displayed by sheets of hexagonal pixels which change temperature very quickly, camouflaging even moving vehicles from heat-sensitive cameras.
- Calcite crystal prism: Calcite crystals send the two polarizations of light in different directions. By fixing prism-shaped crystals together in a particular way, polarised light can be directed around small objects. This effectively cloaks them.
References
Wikiwand in your browser!
Seamless Wikipedia browsing. On steroids.
Every time you click a link to Wikipedia, Wiktionary or Wikiquote in your browser's search results, it will show the modern Wikiwand interface.
Wikiwand extension is a five stars, simple, with minimum permission required to keep your browsing private, safe and transparent.
