【公開日：2023.07.28】【最終更新日：2023.05.30】
課題データ / Project Data
課題番号 / Project Issue Number
22HK0097
利用課題名 / Title
Visualization of quantum coherence under modal strong coupling
利用した実施機関 / Support Institute
北海道大学
機関外・機関内の利用 / External or Internal Use
内部利用（ARIM事業参画者以外）/Internal Use (by non ARIM members)
技術領域 / Technology Area
【横断技術領域 / Cross-Technology Area】（主 / Main）計測・分析/Advanced Characterization（副 / Sub）加工・デバイスプロセス/Nanofabrication
【重要技術領域 / Important Technology Area】（主 / Main）量子・電子制御により革新的な機能を発現するマテリアル/Materials using quantum and electronic control to perform innovative functions（副 / Sub）革新的なエネルギー変換を可能とするマテリアル/Materials enabling innovative energy conversion
キーワード / Keywords
電子顕微鏡/Electron microscopy,電子分光,蒸着・成膜/Evaporation and Deposition,スパッタリング/Sputtering,EB,原子薄膜/ Atomic thin film,量子コンピューター/ Quantum computer,フォトニクス/ Photonics,量子効果/ Quantum effect,表面・界面・粒界制御/ Surface/interface/grain boundary control,電極材料/ Electrode material
利用者と利用形態 / User and Support Type
利用者名（課題申請者）/ User Name (Project Applicant)
Liu Yen-En
所属名 / Affiliation
Hokkaido University, RIES
共同利用者氏名 / Names of Collaborators in Other Institutes Than Hub and Spoke Institutes
ARIM実施機関支援担当者 / Names of Collaborators in The Hub and Spoke Institutes
石 旭,松尾 保孝
利用形態 / Support Type
（主 / Main）機器利用/Equipment Utilization（副 / Sub）-
利用した主な設備 / Equipment Used in This Project
HK-405：時間分解収差補正光電子顕微鏡システム
HK-603：超高速スキャン電子線描画装置(130kV)
HK-616：原子層堆積装置
HK-617：原子層堆積装置（粉末対応型）
HK-609：ヘリコンスパッタリング装置
報告書データ / Report
概要（目的・用途・実施内容）/ Abstract (Aim, Use Applications and Contents)
Previously, our team has demonstrated that the quantum coherence exists between the localized surface plasmon resonance (LSPR) modes of the Au-nanodisks (Au-NDs) under strong coupling with a Fabry-Perot (FP) nanocavity. In this research, we applied photoemission electron microscopy (PEEM) to observe the near-field distribution of the Au-NDs clusters/TiO2/Au-film (ATA) structures as well as the Au-NDs clusters/TiO2 (AT) structures. The observed near-field pattern of ATA strongly suggests the existence of quantum coherence, and by the PEEM measurement, the size of the effective area of the quantum coherence, coherence area, could somehow be estimated.
実験 / Experimental
Sample fabrication:
TiO2 thin film
was deposited by the atomic layer deposition (ALD), and for ATA, a thick
Au-film was deposited by the helicon sputtering beneath the TiO2
film. The Au-NDs were fabricated by the electron-beam lithography, followed by
the Ti (adhesion layer), Au deposition by helicon sputtering, and the lift-off
process. The Au-NDs were arranged as hexagonal clusters with various particle
numbers (PNs). The absorption spectra of the fabricated samples were evaluated to
confirm their qualities.
PEEM measurement:
The clean sample was
delivered into PEEM chamber and annealed multiple times. Then, a -20 kV
of potential was applied to the sample. Under laser pulse irradiation, the emitted electron (photoemission) would be collected by the
objective lens, and the photoemission distribution under a field of view (FOV) could
be visualized by a CCD camera. During measurement, a wavelength tunable (690-900 nm) femtosecond
laser excitation source was used to deliver 100-fs laser pulses with a
bandwidth of approximately 15 nm. The excitation laser was introduced to the
sample at normal incidence with circular polarization. The PE distribution
images were taken under a FOV of f2.5 mm and averaged by 32 times.
結果と考察 / Results and Discussion
The PE patterns under the PE intensity peak wavelength of ATA and AT structures with various PNs were observed. The PE distribution within a Au-NDs cluster of ATA was obviously stronger at the rim of the cluster and the center of the cluster was dark, while that of AT was rather homogeneous compared to ATA. For ATA, the LSPR modes of each Au-NDs could not be considered separately due to quantum coherence. Therefore, when excited by the incident laser, LSPR of the Au-NDs exchange energy with each other, leading to the interference pattern of PE. On the contrary, without quantum coherence, Au-NDs in AT were excited independently by the incident laser, which showed rather homogenous PE distributions.
図・表・数式 / Figures, Tables and Equations
Fig. 1. PE distribution of (a) ATA and (b) AT structures.
その他・特記事項（参考文献・謝辞等） / Remarks(References and Acknowledgements)
成果発表・成果利用 / Publication and Patents
論文・プロシーディング（DOIのあるもの） / DOI (Publication and Proceedings)
口頭発表、ポスター発表および、その他の論文 / Oral Presentations etc.
- 口頭発表: Yen-En Liu et al, The 102nd CSJ annual meeting, Mar. 24th, 2022.
特許 / Patents
特許出願件数 / Number of Patent Applications：0件
特許登録件数 / Number of Registered Patents：0件