Laser beam sends voice, text messages through air
doi:10.1038/nindia.2020.180 Published online 27 November 2020
Physicists have designed a kind of communication system that can send data in the form of voice, text and images over long distances using light1.
The newly designed system can send data through air without deploying fibre-optic cables, the researchers from the Indian Institute of Technology in Guwahati, India, have demonstrated. This mode of data transmission is free from the disturbing effects of atmospheric turbulence, the researchers say.
Previous research had tested vortex beams, a specific type of light beam, to send data through the air. Turbulence caused by wind distorted such data transmission. To overcome this drawback, the IIT scientists used a specific type of laser beam and tested its efficiency in sending data through the air between two stations.
The researchers sent data by modulating the phase profile of the laser beam. A specially designed sensor decoded the laser beam encoded with user information at a receiving station. This process can transmit user information even through a turbulent atmosphere, resulting in negligible error at the receiving station.
The researchers were able to send distortion-free text messages and images over a distance of one kilometre even during stormy weather. The system can thus be used for high-speed and secure communication between two individuals inside or outside a building.
Furthermore, hackers and interlopers cannot breach such a communication system, the researchers say.
1. Konwar, S. et al. Leveraging the orthogonality of Zernike modes for robust free-space optical communication. Comm. Phys. 3:203 (2020)