Quantum Sensor Receives From 0 Hz To 1000 GHz

Although it isn’t that uncommon to have broadband radio coverage in a single device, going from 0 Hz to 1000 GHz with one antenna and receiver is a bit much. But not for the US Army it seems, because they’ve developed a quantum sensor that can cover that range.

The technology uses Rydberg atoms, which are atoms with a highly excited valence electron. They’ve been used for a variety of sensing applications before, such as reading the cosmic microwave background radiation. However, until the Army’s work there has been no quantitative analysis of using them for wide-spectrum communications.

If you want to read more about Rydberg atoms, [Dan Maloney] covered that last year. The basic idea is that one laser beam excites an atom to the Rydberg state and another laser probes the state of the atom. It seems the Army used a single split beam for both jobs with an arrangement of modulators.

The size of the Rydberg sensor was about a centimeter and the experiments compared the sensitivity to other sensors of similar size. Before you get too excited though, the sensor may be small, but the lab to house it isn’t. The team optically pumped rubidium with lasers. We’ve seen quantum radios that require more lab setup, though.

29 thoughts on “Quantum Sensor Receives From 0 Hz To 1000 GHz

  1. Thanks for post :-)
    Hmm, down to zero Hertz is an extraordinary claim – if true could it be possible then to detect wavelengths greater in size than that of a typical solar system or even a EM photon wavelength comparable to the diameter of a supermassive black hole’s event horizon ?

        1. You and several dozen generations of your descendants could live comfortably on the profit alone of a contract like that. I’m thinking it might be something like several times the entire GDP of the Earth…
          Times a million.

      1. North of where I live near Exmouth in Western Australia was a USA submarine communications installation generating radio of 19KHz putting out approx 1.5MW. One of my associates is involved in RF certification and as the test engineer with his instruments flew over the area in one of the early AirBus jets decades ago, during the compliance tests all engine and cockpit electrics power shutdown. They did have battery operated satellite phone to the French engineers who claimed it wasn’t possible and refused to acknowledge a problem. Suffice to say as the jet glided past the area power came back. My understanding is that early transmitter station had a wide range of unusual harmonics below the 19KHz center frequency and the listed power output was likely far less than the actual operating output…

        1. Well, no, I doubt they were transmitting much more power than their 1.5 MW. That’s a rather large transmitter (search Cutler and Jim Creek VLF stations, very impressive). And you don’t just double the power at the flip of a switch. The harmonics are ABOVE the transmitted frequency; and they tend to have filters that stop that stuff. Harmonics waste power, anyhow.

          The radiation efficiency of antennas at that frequency is very low. But if you fly right over them, you’re basically inside a tuned circuit with high currents and voltages. Very easy to overload the front end of a receiver if you overpower them.

        2. The electric field of a half wave dipole radiating 1.5MW at 19KHz comes to 26V/Meter. That is too weak at such a low frequency to damage ordinary equipment and too weak to have any effect inside the skin of an airplane. My friend who was inside a B52 subjected to nuclear weapon equivalent EMP said he never felt anything.

  2. OK, I understand it’s a big lab, and that diode lasers generally have poor coherence on their own. But since I don’t have any means to get through the paywall, can someone tell me about the sensitivity? Also, I am assuming that this puts out baseband RF, and all of the selectivity must come from subsequent electronics.

    The other thing is that we’re not as interested in detectors as we would be in really small antennas that are effective at frequencies far over their resonant length. One can use a large antenna to induce a sttrong local RF field, and do things like preselection electronically. But not as interesting as a quantum antenna that makes such things unnecessary.

    1. That’s easy too, all we need is a material in which the speed of light is about a fast jog. Just grab that order of magnitude dial and twist it back from 8 down to 0. Or we can cheat and just make a little dipole with a pea sized blob of neutrons each end.

      1. Actually the article leads with a span form 0 to 100 GHz, not 1000 GHz. Thus it’s missing 90 % of the band. Later the article says 102 Hz to 1012 GHz which is wider BW — actually 10119999999 Hz wide.
        Secondly a BW of 9.9 G isn’t particularly impressive — your eyes have a BW of about 1000 THz !

        1. It’s percentage bandwidth which is impressive. A 10% bandwidth antenna is “wideband”. Your basic dipole might be a couple percent, depending on how thin it is.

        2. > your eyes have a BW of about 1000 THz !

          No. They can detect a carrier between 399 THz and 789 THz. However, the BW of the signal modulating (AM) that carrier is limited to ~20 Hz under normal conditions. That’s why we can have movies.

          Having said that, human eye after some time in complete darkness can detect single photons, but it needs significant time to relax and be ready for.the next one.

          So no, eyes don’t have BW of about 1000 THz

  3. imagine making a delay line memory with it at a 60 hz framerate, you can process 16,666,666,666 per frame, just treat it as parallel power, and thats full delivery of the entire store.

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