Researchers have successfully developed the world's first superconducting broadband photon detector

Researchers at the National Institute of Information and Communication Technology in the United States have invented a new structure of a superconducting strip photon detector that can achieve efficient photon detection even in wide strips, and have successfully developed the world's first superconducting wide strip photon detector.

The band width of the detector is more than 200 times that of traditional superconducting nanoband photon detectors. This technology helps to solve the problems of low productivity and polarization dependence in traditional SNSPD. The new SWSPD is expected to be applied to various advanced technologies such as quantum information communication and quantum computers, enabling these advanced technologies to be applied in society as soon as possible.

This work is published in the journal Optical Quantum.
Photon detection technology is a strategic core technology that is currently being intensively researched and developed globally in many advanced technology fields such as quantum information communication and quantum computing to achieve innovation. It is also an innovative technology in fields such as live cell fluorescence observation, deep space optical communication, and laser sensing.

The NICT research team has developed an SNSPD with a band width of 100 nm or less. They successfully achieved high-performance beyond other photon detectors and applied them to quantum information communication technology, proving their practicality. 

However, the preparation of SNSPDs requires the use of advanced nanoprocessing techniques to form nanoband structures, which can lead to changes in detector performance and hinder the improvement of productivity. In addition, the polarization dependence of superconducting nanoribbons due to their winding structure also limits their application as photon detectors.

In this work, NICT invented a new structure called "high critical current group structure", which can achieve efficient photon detection even by widening the band width in superconducting strip photon detectors. It successfully developed a SWSPD with a width of 20 microns, which is more than 200 times wider than traditional nanostrip photon detectors, and achieved high-performance operation for the first time in the world.

The nanobelt type developed by NICT requires the formation of extremely long superconducting nanobelts with a bandwidth of 100 nm or less, in a winding and tortuous shape. The broadband type can now be formed using only a single short straight superconducting tape.

This SWSPD does not require nanomachining technology and can be manufactured through high productivity universal lithography technology. In addition, due to the wider bandwidth of the stripe compared to the incident light spot illuminated from the optical fiber, polarization dependence in the nanostrip detector can be eliminated.

Through the performance evaluation of the detector, the detection efficiency in the telecommunications band is 78%, which is equivalent to 81% of the nanoband type. In addition, the numerical value of timing jitter is better than that of nanostrip type.

Compared with the nanobelt type, this achievement enables photon detectors to have higher productivity and superior performance and characteristics. Nanobelt type has been positioned as an indispensable photon detection technology in advanced technology fields such as quantum information communication. This technology is expected to be applied to various quantum information communication technologies and become an important foundational technology for achieving the networked quantum computer advocated by JST's lunar landing goal 6.

In the future, the team will further explore the HCCB structure in SWSPD, which can efficiently detect photons not only in the telecommunications band, but also in a wide range of wavelengths from visible light to mid infrared. In addition, they will also attempt to further expand the size of the photon receiving area to expand applications such as deep space optical communication technology, laser sensing, and live cell observation.

Source: Laser Network