In the classic 1987 sci-fi horror movie "Predator," a fictional character played by Arnold Schwarzenegger is hunted through the jungles of Central America by a technologically advanced alien creature that has an unfair advantage: it can see in thermal infrared.
Now technology developed out of the University of Michigan could even the odds, according to Phys.org. Researchers there are developing a contact lens made of graphene that can sense the whole infrared spectrum — plus visible and ultraviolet light. Users wearing these contact lenses would have high-tech eyesight capable of seeing the world much like the predator does in the movie.
The key to these ultra-cool contact lenses lies in the graphene that they're made from. Graphene is crazy thin, with the thickness of a single atom, making it ideal for use as a contact lens. But this thinness also means that graphene only absorbs about 2.3 percent of the light that hits it, making it problematic as a sensor because the light can't produce an electrical signal.
"The challenge for the current generation of graphene-based detectors is that their sensitivity is typically very poor," said Zhaohui Zhong, one of the researchers developing the technology. "It's a hundred to a thousand times lower than what a commercial device would require."
Zhong and colleagues were able to overcome this problem by looking at how the light-induced electrical charges in the graphene affect a nearby current. This allowed them to amplify the signal.
"Our work pioneered a new way to detect light," Zhong said. "We envision that people will be able to adopt this same mechanism in other material and device platforms."
The researchers constructed their device by putting an insulating barrier layer between two graphene sheets. As light hits the top layer, it frees up electrons, creating "positively charged holes." Electrons then slip through these holes (thanks to a quantum mechanical trick), creating an electrical field that affects the flow of current that runs through the bottom layer. The brightness of the light hitting the graphene can then be deduced by measuring the change in current in the bottom layer.
The whole device is the size of a pinky nail, and can be easily scaled down further, if need be.
"If we integrate it with a contact lens or other wearable electronics, it expands your vision," Zhong said. "It provides you another way of interacting with your environment."
The most immediate use for such a device would be for soldiers in a combat zone. Just like in the "Predator" movies, thermal infrared vision allows users to see clearer in a dark, foggy or heavily camouflaged landscape. Doctors could also use the lenses to monitor blood flow in their patients' bodies.
Of course, the lenses would probably raise privacy concerns if they were sold to everyday consumers. But just imagine how much more of the world you could see if you had the option to turn on thermal infrared or UV eyesight. What would you do with such an ability?
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