Detection of very high frequency magnetic resonance could revolutionize #electronics.
https://phys.org/news/2020-01-high-frequency-magnetic-resonance-revolutionize.html
Terahertz waves (THz) sit between microwaves and infrared in the light frequency spectrum, but due to their low-energy scientists have been unable to harness their potential.
The conundrum is known in scientific circles as the terahertz gap.
Being able to detect and amplify THz waves (T-rays) would open up a new era of medical, communications, satellite, cosmological and other technologies.
One of the biggest applications would be as a safe, non-destructive alternative to X-rays.
https://phys.org/news/2020-02-graphene-amplifier-hidden-frequencies-electromagnetic.amp
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@crackurbones I'm not sure its fair to say "due to their low energy", there are MUCH lower energy frequencies we detect with ease.
@crackurbones I'm aware, but the point is that there is a range we cant detect, but we can detect higher and lower than these ranges.
By the way there are antenna at those sizes. They in our eyes there are special structures ad proteins that are basically antennas of the proper size. It scales rather nicely, in theory, in practice not so much.
@freemo Yeah, not in practice.
In the article, when they have used "due to their low energy", they are referring only to the photodetectors which are able to detect higher frequencies.
They just did not went into explaining the lower-energy waves' detection as the context here -- graphene-based detector, which also responds to energy -- makes the principles of dipole antennas irrelevant.
@freemo Well, to detect the lower-energy frequencies (radio waves, microwaves), we use dipole antennas. To detect optical frequencies, we use optical detectors like photodiodes; these devices respond to, and thus detect, frequencies only above a certain threshold frequency. That's the reason why we aren't able to detect lower frequencies (or lower-energy waves) with photodetectors.
The reason why we are not able to use metallic dipole antennae to detect optical frequencies is because antennae need to have dimension of the order of \lambda/2, and with optical frequencies that is a few nanometers.
I found this paper on Optical Yagi-Uda nanoantennas after a little research on internet: https://arxiv.org/pdf/1204.0330v1.pdf
This creates the "Tetrahertz Gap", a range of frequencies which cannot be detected either by photodetectors ("due to their low energy") or by dipole antennas (because making nano-scale antennas is not feasible).