RIKEN Center for Advanced Photonics Quantum Optoelectronics Research Team

Team Director: Yuichiro Kato (Ph.D.)

Japanese Page

Research Summary

Optoelectronic devices harness the interactions between electrons and photons and are widely used in everyday applications, for example solar cells and light-emitting diodes. Continued advances in device fabrication techniques have enabled the integration of individual nanomaterials into device structures, providing opportunities to utilize the quantum nature of photons. Our research focuses on pioneering and engineering next-generation nanodevices that exploit the quantum properties of nanomaterials and enable control of light at the quantum level. By combining state-of-the-art nanofabrication and nanosynthesis techniques, we investigate devices capable of manipulating single photons in the telecommunication band as well as integrated photonics for quantum applications at room temperature.

Main Research Fields

Interdisciplinary Science & Engineering

Related Research Fields

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

Keywords

optoelectronics
quantum devices
nanoscale devices
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).