Researchers at Harvard University have developed a lasaer pointer that emits, modulates microwaves and receives external radio frequency signals. For the first time, the laser is used as a radio frequency transmitter and receiver, transmitting dean Martin’s classic song “Volare” wirelessly, sci.daily reported. The research paves the way for ultra-fast WiFi and new hybrid electron-photonic devices.
The latest work builds on previous work by a research team led by federico capasso, a senior author and professor of applied physics. In 2017, they discovered that an infrared frequency comb in a quantum cascade laser could be used to generate terahertz, the submillimeter band of the electromagnetic spectrum, which can transmit data hundreds of times faster than today’s wireless platforms. In 2018, they discovered that the frequency comb of a quantum cascade laser could also act as an integrated transmitter or receiver, effectively encoding information.
Now they have found a way to extract and transmit wireless signals from a laser frequency comb.
Unlike conventional lasers, which emit light at a single frequency, the laser frequency comb can emit light at multiple frequencies simultaneously. These rays are evenly spaced and look like comb teeth. Also, inside the laser, light from different frequencies combines to produce microwave radiation.
To transmit microwave signals, the first thing the device needs is an antenna. So the researchers etched a notch in the electrode at the top of the device to create a dipole antenna. Next, they modulated a frequency comb to encode information in microwave radiation (produced by lasers that beat together light of different frequencies). Then, using an antenna, they radiate microwaves from the device, including coded information. Rf signals are received by antennas, filtered and sent to computers.
The researchers also demonstrated that laser radiofrequency can receive signals. They can use microwave signals from other devices to remotely control the laser’s behavior.
“This multifunctional, integrated device is ideal for future wireless communications,” the researchers said. Although the dream of terahertz wireless communication is still a long way off, this research provides a clear roadmap for achieving this goal.”