シリコンナノ球で実現するバレーフォトニクスの新戦略 ―原子1層の半導体から生じる光信号を偏光情報を保ったまま大幅に増強―

2026-03-25 分子科学研究所

図：シリコンナノ球を配置した単層WS₂からのバレー偏光SHG 左：共鳴構造の模式図　右：増強後も高い円偏光度が保持されている

＜関連情報＞

• https://www.ims.ac.jp/news/2026/03/0325.html
• https://pubs.acs.org/doi/10.1021/acs.nanolett.6c00297

Mie共鳴を用いた単層WS2におけるバレー偏光第二高調波発生の同時増強と保存 Simultaneous Enhancement and Preservation of Valley-Polarized Second-Harmonic Generation in Monolayer WS2 via Mie Resonances

Shuto Oh,Mojtaba Karimi Habil,Hiroshi Sugimoto,Minoru Fujii,Kazunari Matsuda,and Keisuke Shinokita
Nano Letters  Published: March 18, 2026
DOI:https://doi.org/10.1021/acs.nanolett.6c00297

Abstract

Second-harmonic generation (SHG) with rigorous polarization preservation is essential for next-generation optical information processing. Monolayer transition-metal dichalcogenides offer an attractive platform for atomically thin, on-chip light sources owing to their valley-dependent polarization selection rules for SHG. However, their atomic-scale thickness severely limits conversion efficiency. To overcome this challenge, nanophotonic structures capable of simultaneously enhancing signal intensity and maintaining high-purity polarization states are required for practical device applications. Herein, we demonstrate the simultaneous resonant enhancement and high-fidelity preservation of valley-polarized SHG in monolayer WS₂ coupled with Mie-resonant silicon nanospheres. We show that the valley polarization state is spectrally modulated by the Mie modes of silicon nanospheres, achieving circular polarization retention of ∼80% within the enhanced spectral regime. These findings establish a robust strategy for manipulating polarization degrees of freedom in integrated nonlinear valley photonics.