Breakthrough in detection of photons

Observation of processes inside live cells, optical communication in deep space, and quantum computers are examples of applications which will benefit from a Japanese technological achievement. Researchers at the National Institute of Information and Communications Technology (NICT) have developed the World’s first superconducting wide-strip photon detector.

Photons are the particles which carry light, and detection of photons is the cornerstone of optical technology. An emerging solution for this task is superconducting strip photon detectors which utilizes the resistance variation of a superconducting strip caused by incident photons. Hitherto, the strips have had to be so thin they could only be manufactured with nanoscale technology, limiting the scope of application.

The NICT researchers have successfully developed superconducting strips over 200 times wider than conventional nanostrips. This will significantly lower fabrication costs and remove various technical hurdles, thereby making superconducting photon detectors feasible for many new applications.

Photon detection is a core technology

Around the globe, intense research and development efforts in quantum computers is taking place. While quantum computers have the potential for outperforming today’s computers to a mind-blowing degree many of the necessary sub-technologies are not yet developed.

One of these sub-technologies is photon detectors for quantum applications. Besides in quantum computers, photon detection is a strategic core technology to bring about innovation in fields such as live cell fluorescent observation, deep space optical communication, and laser sensing.

Previously, NICT succeeded in developing superconducting nanostrip photon detectors with strip widths of 100 nanometer or less. These strips could only be manufactured using nanofabrication technology, which causes variations in detector performance and hinders productivity improvement. In addition, the presence of polarization dependence due to the superconducting nanostrip meandering structure has limited the application range as a photon detector. These limitations have been overcome through the development of the new wide-strip detector.

Can be produced by photo-lithography

In the project, which has been supported by Japan Science and Technology Agency and by Japan Society for the Promotion of Science, NICT invented a novel structure called “high critical current bank structure” that enables highly efficient photon detection even if the strip width is increased. A superconducting wide-strip photon detector with a width of 20 micrometer was successfully produced. This is over 200 times wider than the conventional nanostrip photon detector.

The novel wide-strip detector does not require nanofabrication technology and can be fabricated by highly productive general-purpose photolithography technology. In addition, since the strip width is wider than the incident light spot irradiated from the optical fiber, it is possible to eliminate the polarization dependence seen in the nanostrip type detector.

The text is inspired by the article “Successful development of the World’s first “superconducting wide-strip photon detector”” at the NICT website. The result was originally published in the US scientific journal Optica Quantum.