紙よりはるかに薄い結晶で、光のふるまいをデザイン―ナノメートル厚の結晶の「向き」と「ねじれ」による新しい光制御 ―

2026-03-02 岡山大学,北海道大学

右図A:シリカガラス基板上のMoOCl₂のナノ構造の模式図、B:代表的なMoOCl2の円形ナノ構造の電子顕微鏡写真（半径：87 ナノメーター（nm）、高さ：50 nm、構造間距離：500 nm）、C:反射顕微鏡で測定した構造全体の光学イメージ。上図はMoOCl₂の金属的性質を持つ方向の直線偏光を照射、下図は絶縁体的性質を持つ方向の直線偏光を照射。

＜関連情報＞

• https://www.okayama-u.ac.jp/tp/release/release_id1506.html
• https://www.okayama-u.ac.jp/up_load_files/press_r7/press20260302-1.pdf
• https://www.nature.com/articles/s41467-026-69435-8

異方性2D材料における双曲局在プラズモンとねじれ誘起カイラリティ Hyperbolic localized plasmons and twist-induced chirality in an anisotropic 2D material

Yaolong Li,Xu Shi,Yuxin Zhang,Yen-En Liu,Hong Yang,Guowei Lyu,Yasutaka Matsuo,Xiaoyong Hu,Qihuang Gong & Hiroaki Misawa
Nature Communications　Unedited version

Abstract

Two-dimensional (2D) van der Waals materials with strong in-plane anisotropy are emerging as fertile platforms for nanophotonics beyond conventional isotropic noble metals and dielectrics. Here, we demonstrate hyperbolic localized plasmon resonances (H-LPRs) in MoOCl₂, a representative anisotropic 2D crystal. Unlike conventional plasmons, H-LPRs arise directly from the crystal anisotropy and show unprecedented properties: (i) one-dimensional resonances in circularly symmetric nanodisks, (ii) Z-gap independence in metal–insulator–metal heterostructures, and (iii) twist-induced chirality with circular dichroism values exceeding 0.65. The H-LPRs are characterized by both far-field spectra and near-field imaging. By stacking twisted MoOCl₂ flakes, we bridge H-LPRs with concepts of moiré photonics and twistronics, introducing a new degree of freedom in plasmonic design. These findings establish H-LPRs in anisotropic 2D materials as a generalizable and versatile platform for polarization engineering, ultrasensitive chiral sensing, and integration into compact on-chip and quantum nanophotonic devices.