The very first quantum photonic circuit prepared with an electrical based light source

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Whether for use in ultrafast calculation or secure data encryption of great data volumes or so-known quantum simulation of exceedingly intricate systems, Optical quantum computers are a way of hope for future computer technology. For the very first stance, researchers have now succeeded in placing an absolute quantum optical structure on a single chip. This completed one condition for the utilization of photonic circuits in optical based quantum computers.

“Studies investigating the functionality of optical quantum technology till now have often claimed entire laboratory spaces,” says Professor Ralph Krupke of KIT. “But, if such technology is to be utilized meaningfully, it must be compiled on a less space.” Participants in the research were scientists from Poland, Russia, and Germany under the leadership of Lecturers Wolfram Pernice of the Westphalian Wilhelm University of Munster, Ralph Krupke, and Carsten Rockstuhl.

The source of light for the photonic quantum circuit utilized by the researchers for the very first time was unique nanotubes prepared of carbon. They have a range of 100,000 times tinier than a human hair, and they release a singular light particle when triggered by laser light. Light particles like photons are also considered as light quanta, and hence, have been offered with the term ‘quantum photonics.’

Carbon tubes releasing single photons make them a better option over ultra-compact light sources available for optical quantum computers. “However, it is not convenient to accommodate the advanced laser technology on a single scalable chip,” confirms physicist Wolfram Pernice. The scalability of the device, which is also the feasibility to miniature elements so as to be potential enough to enhance their number, is a pre-requisite for this technology to be utilized in robust computers up to an optical computer based on quantum technology.

Since all the elements on the chip that have now introduced are boosted electronically, without introducing any additional laser systems. It is a marked simplification over the regularly used optical excitation. “The introduction of a scalable chip wherein a single-photon source, waveguide, and a detector are linked together, is a vital step for carrying the research,” says Ralph Krupke, who is a the lead associate of the research and conducted it at the KIT Institute for Nanotechnology as well as the Institute of Materials Science of the Darmstadt Technical Univesity.

“As we were able to reveal that single photon would be able to release also be electronic excitation of the carbon nanotubes, we have combat a limiting factor till now preventing potential applicability.”

If we talk in detail about the technique then the researchers studied whether the electricity flow through nanotubes based on carbon can result in the release of single light quanta or not. For this reason, they employed carbon nanotubes as a source of single-photon, nanophotonic waveguides and superconducting nanowires as detectors. A single-photon source linked with two detectors and each of them connected to a single waveguide. The entire structure was allowed to cool with liquid helium to enable single light quanta to be estimated. The chips were prepared in an electron beam scribing equipment. Till now, it can be confirmed that the work of researchers is a fundamental study and it is still not clear that when it will result in the use of practical applications.