Microchip for room temperature quantum internet

News - 04 December 2019 - Webredactie 3ME

A key requirement for a future quantum internet is that it be widely accessible and afforable. This requires the ability to  prepare mechanical systems in their lowest possible energy state  (the quantum ground state) without expensive cryogenics. Richard Norte, researcher at the Department of Precision and Microsystems Engineering, and his Delft colleagues Simon Groeblacher and Jingkun Guo have managed to design and fabricate a millimetre-long resonator on a chip, which is mechanically isolated from outside room temperature heat and noise. This microchip technology allows them to laser cool a mechanical resonator to near absolute zero while fighting against surrounding room temperature heat. While ultra-cold temperatures as low as 10 mK typically require €250k cryogenic refrigeration with liquid helium, the TU Delft team have been able to cool a mechanical resonator to about 1 mK using only laser light. The team aims to create affordable quantum technologies that do not require cryogenics at all. The outcome of this research is a major step toward accessible, widespread quantum technologies and will lay the groundwork for a new generation of quantum-limited mechanical sensors in ambient environments. The results have been published in Physical Review Letters.

This new microchip technology is based on easy-to-use microchip technology which is already common in sensors and telecom networks (see picture). Laser cooling of optomechanical devices with cryogenics  has been successful at demonstrating ground state preparation of various devices, but a similar demonstration starting from a room temperature environment remains an elusive goal. In their research, the team has combined integrated nanophotonics with phononic metamaterial engineering to simultaneously overcome prior limitations in the isolation from the surrounding ambient environment. By confining light inside this fish-bone nanostructure (see picture), they have been able to enhance their ability to laser cool immensely.

Richard Norte already received an ATTRACT Grant worth 100,000 euros to develop a new generation of quantum accelerometers for interial navigation. The nanotechnologies he has developed at the TU Delft have already produced the world’s most sensitive micro-mirror force sensors. Read more.