Pure and Efficient Single-photon Source Based on Carbon Nanotubes for Quantum Cryptography―Theoretical Discovery of a Technique to Attain a High-performance Single-photon Source at Room Temperature and in the Telecommunication Wavelength Band―
January 28, 2020 Keio University Tokyo Gakugei University
Associate Professor Hideyuki Maki of the Keio University Faculty of Science and Technology, Department of Applied Physics and Physico-Informatics and his collaborators have demonstrated for the first time that a single-photon source that can generate single photons with both high purity and high efficiency at room temperature is theoretically possible through the use of single-walled carbon nanotubes.
Single photons, in which the number of photons contained in a pulse is restricted to one, have recently been attracting attention in quantum information devices such as those for quantum cryptography. To realize highly integrated general-purpose quantum information devices, there is a need for a single-photon source that can generate highly pure and highly efficient single photons at room temperature in the telecommunication wavelength band. To date, Professor Maki's research group has experimentally demonstrated the first single-photon source at room temperature and the telecommunication wavelength using carbon nanotubes, which thereafter has led to research in this area being carried out worldwide. However, it is difficult to generate single photons with both high purity and high efficiency with the current single-photon source, and the development of a technique that can fulfil both of these conditions for practical applications in quantum information devices is highly sought after. In this study, the functionalization of short suspended carbon nanotubes was theoretically demonstrated for the first time as a technique that can generate single photons with both high purity and high efficiency from carbon nanotubes. From this, it became apparent that carbon nanotubes can be used to develop uncooled, high-performance single photon elements in the telecommunication wavelength band, and through the use of this technology, there are expectations that the development of next generation quantum information elements, including general-purpose quantum cryptographic elements with on-chip integration capabilities, will be promoted.
This research was jointly carried out with Associate Professor Yutaka Maeda of Tokyo Gakugei University.
The outcomes of this research were published on the online issue of ACS Applied Nano Materials, a scientific journal published by the American Chemical Society (ACS), on December 27, 2019.
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