Chief Scientist Laboratories Nanoscale Quantum Photonics Laboratory

Chief Scientist: Yuichiro Kato (Ph.D.)

Japanese Page

Research Summary

Quantum technologies are expected to make important developments in various fields of engineering including computing, sensing, metrology, and communication. Since quantum effects become more evident and more robust as the system scales down, devices with atomically precise elements could provide a route for quantum technologies operating at elevated temperatures. Our research focuses on the optical properties of nanomaterials and the physics of nanoscale photonic devices, investigating new approaches for utilizing their quantum properties. By engineering atomically defined nanostructures and integrating them into nanoscale devices, we explore novel concepts in photonics for future quantum technologies.

Main Research Fields

Interdisciplinary Science & Engineering

Related Research Fields

Mathematical & Physical Sciences
Chemistry
Engineering
nanostrucutre physics
optical engineering and photon science

Keywords

optical properties
nanoscale physics
device physics
carbon nanotubes
photonic crystals

Selected Publications

Papers with an asterisk(*) are based on research conducted outside of RIKEN.

1. D. Yamashita, N. Fang, S. Fujii, Y. K. Kato:
"Hybrid silicon all-optical switching devices integrated with 2D material"
Adv. Opt. Mater. 13, 2402531 (2025).
2. D. Kozawa, S. Fujii, Y. K. Kato:
"Intrinsic process for upconversion photoluminescence via K-momentum-phonon coupling in carbon nanotubes"
Phys. Rev. B 110, 155418 (2024). [Editors' Suggestion]
3. C. F. Fong, D. Yamashita, N. Fang, S. Fujii, Y.-R. Chang, T. Taniguchi, K. Watanabe, Y. K. Kato:
"Self-aligned hybrid nanocavities using atomically thin materials"
ACS Photonics 11, 2247 (2024).
4. N. Fang, Y. R. Chang, S. Fujii, D. Yamashita, M. Maruyama, Y. Gao, C. F. Fong, D. Kozawa, K. Otsuka, K. Nagashio, S. Okada, Y. K. Kato:
"Room-temperature quantum emission from interface excitons in mixed-dimensional heterostructures"
Nature Commun. 15, 2871 (2024).
5. S. Fujii, N. Fang, D. Yamashita, D. Kozawa, C. F. Fong, Y. K. Kato:
"van der Waals decoration of ultra-high-Q silica microcavities for χ⁽²⁾-χ⁽³⁾ hybrid nonlinear photonics"
Nano Lett. 24, 4209 (2024).
6. N. Fang, Y. R. Chang, D. Yamashita, S. Fujii, M. Maruyama, Y. Gao, C. F. Fong, K. Otsuka, K. Nagashio, S. Okada, Y. K. Kato:
"Resonant exciton transfer in mixed-dimensional heterostructures for overcoming dimensional restrictions in optical processes"
Nature Commun. 14, 8152 (2023).
7. D. Kozawa, X. Wu, A. Ishii, J. Fortner, K. Otsuka, R. Xiang, T. Inoue, S. Maruyama, Y. Wang, Y. K. Kato:
"Formation of organic color centers in air-suspended carbon nanotubes using vapor-phase reaction"
Nature Commun. 13, 2814 (2022).
8. K. Otsuka, N. Fang, D. Yamashita, T. Taniguchi, K. Watanabe, Y. K. Kato:
"Deterministic transfer of optical-quality carbon nanotubes for atomically defined technology"
Nature Commun. 12, 3138 (2021).
9. A. Ishii, H. Machiya, Y. K. Kato:
"High efficiency dark-to-bright exciton conversion in carbon nanotubes"
Phys. Rev. X 9, 041048 (2019).
10. *Y. K. Kato, R. C. Myers, A. C. Gossard, D. D. Awschalom:
"Observation of the spin Hall effect in semiconductors"
Science 306, 1910 (2004).