University of Otago physicists have used a small glass bulb containing an atomic vapor to demonstrate a new form of antenna for radio waves. The bulb was "wired up" with laser beams and could therefore be placed far from any receiver electronics.
In particular, this happens for RF frequencies that couple the Rydberg level resonantly to other nearby Rydberg levels. For sufficiently large fields, the atoms are receptive to a broad range of RF signals via the AC Stark shift.
meaning there’s physical limit on where these bands need to be, outside of these regions it’s less sensitive, and it’s mostly microwaves anyway (authors tested 16-20GHz)
we are able to make very compact extremely broadband receive (and also transmit) antennas for microwave bands, it’s a log spiral antenna backed with cavity. easily can reach to over 40GHz, much simpler, smaller (counting all optics) and probably with much better sensitivity. already used in radar warning receivers, and has nice property that on lower end it’s limited by size, but on upper end on precision of the central section - so can be made really wideband
also that’s really just a transducer, still needs a box with lasers and some other machinery that allows for demodulating that optical signal. “RF detector that doesn’t contain metal” is a weird advantage because there’s usually a large amount of metal connections required to actually do something useful with that freshly collected signal
I would probably argue that it’s not so much pointless as it currently has more limited use cases than conventional means. This may or may not change in the future.
also that’s really just a transducer, still needs a box with lasers and some other machinery that allows for demodulating that optical signal. “RF detector that doesn’t contain metal” is a weird advantage because there’s usually a large amount of metal connections required to actually do something useful with that freshly collected signal
30m away (that’s longer than a basketball court!), though, and probably more because this demo was “no particular effort”. I don’t know the use case, but I’m guessing it’s not a home router.
that’s great, however
meaning there’s physical limit on where these bands need to be, outside of these regions it’s less sensitive, and it’s mostly microwaves anyway (authors tested 16-20GHz)
we are able to make very compact extremely broadband receive (and also transmit) antennas for microwave bands, it’s a log spiral antenna backed with cavity. easily can reach to over 40GHz, much simpler, smaller (counting all optics) and probably with much better sensitivity. already used in radar warning receivers, and has nice property that on lower end it’s limited by size, but on upper end on precision of the central section - so can be made really wideband
also that’s really just a transducer, still needs a box with lasers and some other machinery that allows for demodulating that optical signal. “RF detector that doesn’t contain metal” is a weird advantage because there’s usually a large amount of metal connections required to actually do something useful with that freshly collected signal
actual article https://pubs.aip.org/aip/apl/article/123/14/144003/2914151/Distant-RF-field-sensing-with-a-passive-Rydberg
ahh its pointless
I would probably argue that it’s not so much pointless as it currently has more limited use cases than conventional means. This may or may not change in the future.
30m away (that’s longer than a basketball court!), though, and probably more because this demo was “no particular effort”. I don’t know the use case, but I’m guessing it’s not a home router.