Shanghai Microsystems Institute has developed a high-speed photon detector with distinguishable photon numbers

Recently, Li Hao and You Lixing's team from the Chinese Academy of Sciences Shanghai Institute of Microsystems and Information Technology developed an ultrahigh speed, photon number resolvable optical quantum detector with a maximum count rate of 5GHz and a photon number resolution of 61 by using the sandwich structure superconducting nanowires and multi wires working in parallel. The related research results, titled "Superconducting single photon detector with speed of 5 GHz and photon number resolution of 61", were published online in Photonics Research and were selected for editorial recommendation.

In recent years, superconducting nanowire single photon detectors have been widely used in quantum communication, optical quantum computing, and quantum mechanics principle verification due to their high efficiency, low dark count rate, and excellent time resolution.

The team has developed a highly efficient, ultra high speed, and high photon resolution superconducting detector integrated system. To ensure the portability and reliability of the detection system, the project has built a cooling integrated system based on a GM small refrigeration mechanism. The system supports 64 electrical channels and has a minimum operating temperature of 2.3 K. The detector chip integrates 64 superconducting nanowires on a distributed Bragg reflector, achieving both improved photon absorption and detection speed. After characterization, the yield of nanowire preparation was 61/64, and the system detection efficiency reached 90% at a wavelength of 1550 nm. The maximum counting rate was 5.2 GHz, and the counting rate was 1.7 GHz when the detection efficiency decreased by 3dB. The photon number resolution was 61. The performance indicators of this detection system are expected to support applications such as deep space laser communication, high-speed quantum communication, and basic quantum optical experiments.

The research work was supported by the Science and Technology Innovation 2030 Major Project, the National Natural Science Foundation of China, the Youth Innovation Promotion Association of the Chinese Academy of Sciences, and the "Sailing Plan" of Shanghai.

Device structure (a), superconducting nanowires (b), device packaging (c), and refrigeration system (d)

Source: Shanghai Institute of Microsystems and Information Technology, Chinese Academy of Sciences