Self-trapped exciton-phonon resonance enhanced nonlinear susceptibility in 2D KNbO2

IF 3.5 2区物理与天体物理 Q2 PHYSICS, APPLIED

Applied Physics Letters Pub Date : 2024-11-26 DOI:10.1063/5.0239364

Fei Zhou, Zhiyuan Yang, Jingtao Huang, Xueping Zheng, Xianhua Wei, Bo Dai

引用次数: 0

Abstract

Strong second harmonic generation (SHG) was observed when the two-photon energy matches to the self-trapped exciton resonance states in the lattice inversion symmetric system of two-dimensional (2D) KNbO2 crystals. It is ascribed to the symmetry broken induced by the bending distortion of O−Nb−O in individual octahedrons (low frequency T2g modes) that coupling to the two-photon frequency. The quantum confinement SHG response with more than one orders of enhancement is obtained due to the phonon-exciton-photon interaction with dimension reduction. In addition, the exciton-phonon interaction couples SHG photons to a non-equilibrium energy with a Stokes or anti-Stokes energy splitting of ∼18–21 meV, which is corresponding to the Raman shift of T2g modes.

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二维 KNbO2 中自俘获激子-声子共振增强的非线性易感性

在二维（2D）KNbO2 晶体的晶格反转对称体系中，当双光子能量与自俘获激子共振态相匹配时，观察到了强烈的二次谐波发生（SHG）。这是由于单个八面体中 O-Nb-O 的弯曲变形（低频 T2g 模式）引起的对称性破坏与双光子频率耦合所致。由于声子-激子-光子相互作用的维度降低，量子约束 SHG 响应得到了一个数量级以上的增强。此外，激子-光子相互作用将 SHG 光子耦合到非平衡能量，其斯托克斯或反斯托克斯能量分裂为 18-21 meV，这与 T2g 模式的拉曼位移相对应。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Applied Physics Letters 物理-物理：应用

CiteScore

6.40

自引率

10.00%

发文量

1821

审稿时长

1.6 months

期刊介绍： Applied Physics Letters (APL) features concise, up-to-date reports on significant new findings in applied physics. Emphasizing rapid dissemination of key data and new physical insights, APL offers prompt publication of new experimental and theoretical papers reporting applications of physics phenomena to all branches of science, engineering, and modern technology. In addition to regular articles, the journal also publishes invited Fast Track, Perspectives, and in-depth Editorials which report on cutting-edge areas in applied physics. APL Perspectives are forward-looking invited letters which highlight recent developments or discoveries. Emphasis is placed on very recent developments, potentially disruptive technologies, open questions and possible solutions. They also include a mini-roadmap detailing where the community should direct efforts in order for the phenomena to be viable for application and the challenges associated with meeting that performance threshold. Perspectives are characterized by personal viewpoints and opinions of recognized experts in the field. Fast Track articles are invited original research articles that report results that are particularly novel and important or provide a significant advancement in an emerging field. Because of the urgency and scientific importance of the work, the peer review process is accelerated. If, during the review process, it becomes apparent that the paper does not meet the Fast Track criterion, it is returned to a normal track.