A group of researchers from the University of Sydney in Australia have developed a "photonic microchip" that converts light pulses into data, via sound waves. The chip does not produce any heat, it is immune to electromagnetic interference, and it's supposed to be 20 times faster than current CPUs.
https://www.notebookcheck.net/Scientists-envision-the-optical-computer-light-and-sound-waves-transformed-into-data.249388.0.html