Boost for quantum computing

1 min read

In what could be a boost for quantum computing and communication, a team of European scientists have reported a new method of controlling and manipulating single photons without generating heat.

The solution makes it possible to integrate optical switches and single-photon detectors in a single chip.

The European Quantum Flagship project, S2QUIP, is reported to have developed an optical switch that is reconfigured with microscopic mechanical movement rather than heat, making the switch compatible with heat-sensitive single-photon detectors.

Currently, optical switches work by locally heating light guides inside a semiconductor chip. "This approach does not work for quantum optics," said Samuel Gyger, a researcher from the KTH Royal Institute of Technology in Stockholm.

"Because we want to detect every single photon, we use quantum detectors that work by measuring the heat a single photon generates when absorbed by a superconducting material. If we use traditional switches, our detectors will be flooded by heat, and wont work at all."

The new method enables control of single photons without the disadvantage of heating up a semiconductor chip and rendering single-photon detectors useless.

By using MEMS actuation it is possible to enable optical switching and photon detection on a single semiconductor chip while maintaining the cold temperatures required by single-photon detectors.

"Our technology will help to connect all building blocks required for integrated optical circuits for quantum technologies," said Errando Herranz, who led the work at KTH.

"Quantum technologies will enable secure message encryption and methods of computation that solve problems today's computers cannot and they will provide simulation tools that enable us to understand fundamental laws of nature, which can lead to new materials and medicines."

Herranz said that the group is looking to integrate the fabrication process in semiconductor foundries that already fabricate on-chip optics - a

necessary step in order to make quantum optic circuits large enough to fulfill some of the promises of quantum technologies.