In a previous article, we explored the realm of smart textiles and the elusive distance to realization. Invisibility cloak from Harry Potter Fictional characters such as Predator Alien. But recent developments suggest that Chinese scientists may have brought us closer to JK Rowling’s fantastical structure. The inventor claims that one day the invisibility cloak could become a fashionable wardrobe accessory for everyone. How was this breakthrough achieved?
How the invisibility cloak works
The basic principle of the invisibility cloak is as follows. Manipulate the light beam and direct it to reach the object behind the cloak.. Essentially, the goal is to bend light, since traditional reactions either absorb light to hide the background, or reflect light to illuminate and reveal objects. Three main approaches are considered to achieve hiding:
- Metamaterial: Theoretical methods include the use of metamaterials, materials intentionally designed with electromagnetic properties that do not occur naturally. These materials can bend or deflect light around objects, making them invisible to the naked eye.
- Optical operation: Other research explores manipulating light using lenses and optical devices to bend it around objects, effectively making it invisible.
- Camouflage technology: The third option utilizes cameras and projectors to create the illusion of being invisible. A camera captures the image and a projector plays it back from the other side, creating a sense of transparency.
Donghua University’s Invisibility Cloak
At a recent scientific conference in Shanghai, Professor Chu Junhao of Donghua University announced what appears to be: The most realistic invisibility cloak ever. During the demonstration, he described it as a sheet featuring multiple rows of cylindrical convex lenses. Each lens can compress objects parallel to it, causing refraction of light. As a result, the image is fragmented into millions of identical particles, which are indistinguishable to the human eye. Junhao claims the technology is poised to “change our lives.”
To witness the technology in action, check out the video uploaded to X that showcases its features. At first, the researcher’s feet are visible through the panel, but they become blurry. As the two figures chase him back, the researcher and his captors disappear, revealing the background of the scene.
magic! Zhu Junhao, a scholar at the Chinese Academy of Sciences, demonstrated “invisibility.” pic.twitter.com/qNESHCVvPK
— Zhang Heqing (@zhang_heqing) October 30, 2023
A brief history of invisible history in 10 milestones
Although invisible technology is prominent in books and fiction such as H.G. Wells’ The Invisible Man, the Star Trek series, and the examples mentioned above; has been the subject of scientific exploration for decades. Although not as spectacular as the development by the team at Donghua University, recent years have witnessed important milestones in the progress of invisibility cloaks. Here are some key moments.
- 2006: Researchers at Duke University in the US have unveiled the first cloak that is limited to two dimensions and works only with microwaves.
- 2007: The British Army is experimenting with an “invisible” tank that uses a combination of cameras and projectors to create a fictitious image that hides the vehicle.
- 2008: The University of California is conducting initial tests of a metamaterial that redirects visible and infrared light to achieve invisibility effects.
- 2010: Nature reports that two scientists are working on a metamaterial derived from calcite crystals that would enable cost-effective invisibility.
- 2011: The University of Texas is demonstrating advances in invisibility using carbon nanotubes.
- year 2012: Duke University has achieved another breakthrough. Its invisibility system can completely hide objects as small as a few centimeters.
- 2013: The University of Texas has refined the invisible technology to achieve the effect with a material just 0.15 mm thick.
- 2014: The University of Rochester has successfully made objects as small as a few centimeters invisible, regardless of the observer’s position.
- 2015: A National Science Foundation scientist has won the Waterman Prize for creating a metamaterial that can mask three-dimensional objects.
- 2019: A Canadian company specializing in camouflage clothing has unveiled Quantum Stealth, a paper-thin material that uses lenticular lenses to conceal soldiers and vehicles.
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