Using Acoustic Waves in Microchips Could Lead to Faster Signal Processing

According to researchers from the University of Sydney Nano Institute and Max Planck Institute for the Science of Light, chips that use light and sound, rather than electricity, will be important for the development of future tech, such as high-speed internet as well as radar and sensor technology. This will require the low-heat, fast transmission of information. Scientists in Australia and Europe have taken an important step towards removing ‘hot’ electrons from the data chips that are a driving force in global telecommunications. Microchips without electrons will allow for the invention of data processing systems that don't overheat, have low energy costs, and reduce greenhouse gas emissions. This foundational work will help scientists invent systems to achieve those aims.

As demand for high bandwidth information systems increase, researchers want to get ahead of the curve to ensure the invention of those devices that don’t overheat, have low energy costs and reduce the emission of greenhouse gases. The idea is to use sound waves, known as phonons, to store and transfer information that chips receive from fibre-optic cables. This allows the chips to operate without needing electrons, which produce heat. The Australian and European team was the first in the world to successfully manage this process on-chip.

However, information transferred from fiber-optic cables onto chips in the form of sound waves decays in nanoseconds, which is not long enough to do anything useful. The researchers used carefully timed synchronized pulses of light to reinforce the sound waves on-chip. They have shown for the first time that refreshing these phonons is possible and that information can, therefore, be stored and processed for a much longer time.

The scientists carefully timed pulses of light to extend the lifetime of the information stored in sound waves on the chip by 300 percent, from 10 nanoseconds to 40 nanoseconds. They are planning to use this method to extend how long the information remains on-chip. Acoustic waves on chips are a promising way to store and transfer information. So far, such storage was fundamentally limited by the lifetime of the sound waves. Refreshing the acoustic waves allows to overcome this constraint.

Theoretically, this concept can be extended to the microsecond regime. This proof-of-principle demonstration opens many possibilities for optical signal processing, fine filtering, high-precision sensing and telecommunications.

This research work, published in the journal Optica, was done in collaboration with the Laser Physics Centre at the Australian National University and the Centre for Nano-Optics at the University of Southern Denmark.