The development comes from the Harvard John A. Paulson School of Engineering and Applied Sciences, where researchers have successfully transmitted a recording of Dean Martin singing the song “Volare” (or Nel blu, dipinto di blu, to give the Domenico Modugno. Track its official title) wirelessly.
The wireless transmission of the popular easy-listening tune was achieved via a semiconductor laser. The study also showed how a laser can be conditioned so it emits microwaves wirelessly, and how it can be used to modulate the microwaves. The equipment was also capable of receiving external radio frequency signals.
The technology was built upon earlier work where it was demonstrated how an infrared frequency comb, within a quantum cascade laser, can be equipped to generate terahertz frequencies. These are the sub-millimeter wavelengths of the electromagnetic spectrum theoretically capable of moving data hundreds of times faster than conventional wireless platforms.
The researchers also established that that quantum cascade laser frequency combs are also capable of functioning as either integrated transmitters or receivers, which enables them to efficiently encode information.
The second stage of the research was to apply the earlier technology to extract and transmit wireless signals from laser frequency combs. The most complex part was developing an antenna. For this the science team etched a gap into the top electrode of the device, to produce a dipole antenna. Following this the researchers modulated the frequency comb in order to encode information on the microwave radiation, which was created by the beating light of the comb.
Finally, deploying the antenna, the researchers allowed the microwaves to be radiated out from the device, with the microwaves containing the encoded information. The radio signal produced is then received by another antenna and sent to a computer for digital interpretation.
Speaking with Phys.org, lead researcher Marco Piccardo states: “This all-in-one, integrated device holds great promise for wireless communication,” said Piccardo. “While the dream of terahertz wireless communication is still a ways away, this research provides a clear roadmap showing how to get there.”
The research has been published in the journal Proceedings of the National Academy of Sciences, with the research paper titled “Radio frequency transmitter based on a laser frequency comb.”
