INTRODUCTION:
A cloaking device is a hypothetical or fictional stealth technology that can cause objects, such as spaceships or individuals, to be partially or wholly invisible to parts of the electromagnetic (EM) spectrum. Fictional cloaking devices have been used as plot devices in various media for many years.
Developments in scientific research show that real-world cloaking devices can obscure objects from at least one wavelength of EM emissions. Scientists already use artificial materials called metamaterials to bend light around an object. However, over the entire spectrum, a cloaked object scatters more than an uncloaked object
METASCREEN:
A prototype Meta screen is a claimed cloaking device, which is just few micrometers thick and to a limited extent can hide 3D objects from microwaves in their natural environment, in their natural positions, in all directions, and from all of the observer’s positions. It was prepared at the University of Texas at Austin by Professor Andrea.
The Meta screen consisted of a 66 micrometer thick polycarbonate film supporting an arrangement of 20 micrometer thick copper strips that resembled a fishing net. In the experiment, when the Meta screen was hit by 3.6 GHz microwaves, it re-radiated microwaves of the same frequency that were out of phase, thus cancelling out reflections from the object being hidden. The device only cancelled out the scattering of microwaves in the first order. The same researchers published a paper on “plasmonic cloaking” the previous year.
WORKINGS:
- Metamaterials : These materials passively shield objects from electromagnetic waves.
- Active cloaking : Devices generate electromagnetic fields that distort waves.
- Retro-reflection : Glass beads bend light rays so that they travel back along the same path as they came in.
DISADVANTAGES:
Current meta-materials that provide even limited cloaking are only good for a narrow range of frequencies in the microwave spectrum, are hilariously expensive, and terribly fragile.
APPLICATIONS:
- Defense : Cloaking technology could be used to make military vehicles or ships invisible.
- Search engine optimization : Cloaking can be used to display different content to users than search engine crawlers.
- Medical imaging : Acoustic cloaking technology could be used to improve ultrasound scans and seismic maps.
- Ocean waves : Cloaking technology could be used to protect coastlines from ocean waves.
