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In the sixth episode of season two, “Second Truths”, we see Kiera go up against the mysterious serial killer known in 2077 as the Ouroboros Killer. Using her knowledge of the case in 2077, Kiera (Rachel Nichols) discovers that there isn’t one but two killers working together. We see Kiera’s cellular memory review/recall or CMR in action and that her cybernetic visual implants allow her to see in low light and the infra-red spectrum
We also see a further use of Kiera’s night vision capabilities in the episode “Minute of Silence”. Both Kiera and Carlos (Victor Webster) track a high-tech free running thief who has stolen an invisibility cloak from Hyper Stealth. Though invisible to visible light, Kiera’s CMR picks up the thief’s heat signature and she and Carlos are able to make a quick arrest.
Night vision isn’t exactly new. It has been used by the military as far back as World War II. Present day night vision devices look like binoculars strapped onto a soldier’s helmet; not like Kiera’s cybernetic visual implants which have been neatly implanted onto her eyes. A device like this may not be that far off in the future. Engineers from the University of Michigan have built and tested a broadband photodetector using graphene, a honeycomb lattice of carbon atoms that is just one atom thick. Their findings was published in 2014 in the prestigious journal Nature Nanotechnology. The study’s authors hope this will one day lead to night vision contact lens.
The Science of Night Vision
It should come as no surprise that many animals have better night vision than humans do. They can either see a much wider range of the light spectrum or see at much lower light levels than we do. Humans, instead, use technology to improve upon what nature hasn’t given us. This works in one of two ways: either by image enhancement or by thermal imaging.
In image enhancement, low light levels, that are imperceptible to our eyes, are amplified to a point where we can observe an image. In thermal imaging, the infrared part of the spectrum is captured with an infrared detector and converted into visible light to produce an image.
The Miracle of Graphene
A futuristic science fiction device could be based on nanotechnology and made using graphene, a sheet of carbon that is just one atom thick. The carbon atoms form strong covalent bonds and are arranged in a hexagonal shape. This gives graphene unparalleled strength not seen in most materials; its breaking strength is over 100 times greater than a hypothetical steel film of the same thickness.
The material was discovered in 2004 by two University of Manchester physicists, Andre Geim and Kostya Novoselov. The two scientist pulled tiny bits of graphene from a lump of graphite, the same material found in a “lead” pencil, by sandwiching a graphite flake between some Scotch Tape. The tape layers was pulled apart to separate the atomic layers. They continued this process several times until a single atomic layer was left on the Scotch Tape.
What may come as a surprise to the average non-scientist is that no special equipment is needed to view this single atomic layer of carbon atoms. Graphene is considerable opaque considering it’s only one atom thick. The layer absorbs 2.3% of the light incident on it making it very easy to see with the naked eye.
If this 2.3% doesn’t sound impressive, that is because it really isn’t. Compared to a material like silicon, which is used to make solar cells, it doesn’t absorb as many photons. However, it does have one advantage over silicon–it has no band gap.
Band gaps exist in both insulators and semiconductors and is the energy needed to get electrons flowing in either material. Metals conduct easily because their valence and conduction bands overlap and require no additional energy to get them moving. Semiconductors can get this energy from light. If a photon with enough energy strikes the surface of a semiconductor, it knocks and electron loose and the material starts conducting. If there isn’t enough then it remains an insulator.
If a photon has more energy than the required amount, then the extra energy is lost unless it has twice the energy of the band gap. In this case the photon will liberate two electrons. This is the reason why, under ideal conditions, the silicon based solar cells maximum efficiency is about 30%; they can only absorb photons with energy in a tiny range. Graphene has, what is known as, a zero band gap which means they can absorb photons of all energies. So while it doesn’t absorb as many photons as silicon, it makes better use of the much wider range of photons that it does absorb. This is of considerable interest to scientists as they could become highly efficient solar cells.
Kiera’s Cybernetic Visual Implants
Kiera’s cybernetic visual implants form part of her CMR or cellular memory review. The CMR is based on a liquid chip technology that interfaces with the visual implants to give users a Heads-Up Display. The visual implants also allow its users to see beyond the visual range, to detect infra-red radiation and see in low light conditions.
Present day night vision devices are clunky. Devices that can see in the low-IR region typically requires detectors to be cryogenically cooled to reduce their atom’s thermal vibrations as much as possible. Neither of these characteristics are ideal for the future of law enforcement. Future City Protective Services’ (CPS) Protectors will need to carry liquid-nitrogen cryogenic backpacks for their visual implants to work effectively.
Graphene may solve this problem as it is also able to absorb infra-red photons at room temperature. The problem is that it doesn’t absorb a whole lot of infra-red photons. Its sensitivity is about one hundred to one thousand times lower than any commercial device on the market; any signal it produces will be too weak to produce an image. Researchers at the University of Michigan, led by Zhaohui Zhong, have found a way to capture and amplify the signal into a device smaller than a pinky nail.
The IR detector is created by sandwiching an insulating layer between two sheets of graphene. A tiny electrical current runs through the bottom sheet. Electrons are released as infrared photons strike the top graphene layer. These free electrons quantum tunnel through the insulating layer where changes in current flow in the bottom layer is measured and observed. Zhong and his team were able to use this to determine the brightness of light striking the upper layer and create a viable method of detecting infra-red radiation in something that could, one day, fit inside a contact lens.
We have seen Kiera monitor physiological function and identify chemicals using her CMR. This graphene-based device could also, one day, go beyond military and law-enforcement applications to use IR-wavelengths to monitor blood flow as well as identify chemicals from their heat signature. Could the tech we see on Continuum become a part of wearable electronics that will expand our vision and provide us with another way to work and interact with our environment?