You’ve never heard Dean Martin like this.

This recording of Martin’s classic “Volare” was transmitted wirelessly via a semiconductor laser — the first time a laser has been used as a radio frequency transmitter.

In a paper published in the Proceedings of the National Academy of Sciences, researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) demonstrated a laser that can emit microwaves wirelessly, modulate them, and receive external radio frequency signals.

“The research opens the door to new types of hybrid electronic-photonic devices and is the first step toward ultra-high-speed Wi-Fi,” said Federico Capasso, the Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering at SEAS and senior author of the study.

This research builds off previous work from the Capasso Lab. In 2017, the researchers discovered that an infrared-frequency comb in a quantum cascade laser could be used to generate terahertz frequencies, the submillimeter wavelengths of the electromagnetic spectrum that could move data hundreds of times faster than today’s wireless. In 2018, the team found that quantum cascade laser frequency combs could also act as integrated transmitters or receivers to efficiently encode information.

The song “Volare” by Dean Martin is transmitted via a laser frequency comb, the first time a laser has been used as a radio transmitter.

Now, the researchers have figured out a way to extract and transmit wireless signals from laser frequency combs.

Unlike conventional lasers, which emit a single frequency of light, laser frequency combs emit multiple frequencies simultaneously, evenly spaced to resemble the teeth of a comb. In 2018, the researchers discovered that inside the laser, the different frequencies of light beat together to generate microwave radiation. The light inside the cavity of the laser caused electrons to oscillate at microwave frequencies — which are within the communications spectrum.

“If you want to use this device for Wi-Fi, you need to be able to put useful information in the microwave signals and extract that information from the device,” said Marco Piccardo, a postdoctoral fellow at SEAS and first author of the paper.