Scientists have created an atomic-scale radio receiver using a diamond crystal and a laser:
Physicists at Harvard have built a radio receiver out of building blocks the size of two atoms. It is, almost certainly, the tiniest radio receiver in the world. [...] The researchers replace some of those carbon atoms with nitrogen atoms, and leave a hole next to each one. That nitrogen atom/hole pair, called a nitrogen-vacancy center, basically creates the first two parts of the radio: the power source and the receiver.
A green laser pointed at the nitrogen-vacancy center excites the electrons in the diamond. That's the power. When a radio wave hits those excited electrons around the nitrogen-vacancy center, it's converted into red light. That's the receiver. It's also one of the reasons nitrogen-vacancy centers are so compelling as a building block for tiny machines -- they are natural light emitters. An electromagnet near the receiver can change the frequency to which the receiver is sensitive. That's the tuner. But at that point, your "radio" is just a glowing red light. It still hasn't made any sounds.
For the last step, a common device called a photodiode converts the red light back to an electrical current, and a speaker or pair of headphones grabs that current and broadcasts it as sound.
Also at Harvard.
Diamond Radio Receiver: Nitrogen-Vacancy Centers as Fluorescent Transducers of Microwave Signals (DOI: 10.1103/PhysRevApplied.6.064008) (DX)
(Score: 2, Interesting) by DmT on Thursday December 22 2016, @07:49AM
So they still are making modern smartphones without FM radio, because the size does not allow to fit the FM radio?
Did they also count the laser and the power supply for the laser towards the size?
(Score: 0) by Anonymous Coward on Thursday December 22 2016, @10:15AM
What are you talking about, all of my smartphones have had an FM radio (Nexus one, Huawei G510, Sony Experia Z1, Sony Experia Z5)?
(Score: 0) by Anonymous Coward on Thursday December 22 2016, @06:03PM
I assume it is disabled on certain smartphones as an anti-competitive move (get them using iTunes instead).
(Score: 3, Informative) by Francis on Thursday December 22 2016, @10:21AM
They've been there for years, the issue is that they usually don't include the software to make it work. As the AC points out as early as the Nexus One, the hardware was there to make it happen, it's just that the software didn't enable it. IIRC, you could get the software to enable it, but that required rooting the phone. CyanogenMod had it enabled along with a few other niceties like different colors on the wheel that were inexplicably disabled in the official firmware.
(Score: 2) by mcgrew on Thursday December 22 2016, @04:10PM
Size can't be the reason all phones don't have radios (I'm tempted to mod you "funny" since a phone is a computer with multiple radios). My Samsung tablet won;t pick up FM except from an internet stream, and I should be able to watch broadcast TV on the damned thing; all the hardware to do so is there.
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