报告时间：2023年4月6日（星期四）下午4:10
报告地点：仲英楼B241
报告人：雷党愿 副教授
报告人简介：
雷党愿，伦敦帝国理工学院博士，香港城市大学材料科学及工程学系副教授，博士生导师，香港青年科学院院士，国家“优秀青年科学基金（港澳）”和香港研资局“杰出青年学者计划基金”获得者。2005年从西北大学物理学系获得学士学位，2007年在香港中文大学物理学系获得硕士学位，2011年从伦敦帝国理工学院物理学系获得博士学位，随后留校从事博士后研究工作。2012年9月加入香港理工大学应用物理学系任助理教授，随后于2019年1月加入香港城市大学任副教授，获终身教职。长期从事低维量子材料及结构的纳米光子学研究，及其在微纳光电子器件、高分辨光学成像、单分子量子传感、信息加密与处理以及能量转换、存储与节能方面的应用。迄今共发表学术论文近200篇，其中近100篇文章影响因子大于10，谷歌学术总引用近10000次，h-index是56。三篇文章分别被Science杂志作为Editor’s Choice和Nature Materials杂志作为Research Highlights报道，五篇文章分别入选英国皇家化学学会Journal of Materials Chemistry A和Journal of Materials Chemistry C杂志Emerging Investigators专刊、英国物理学会Journal of Optics杂志Emerging Leaders专刊、Wiley EcoMat杂志Young Investigator专刊以及the list of Top 50 Most Read Nature Communications Articles of 2020 in Physics。
雷博士曾获得香港城市大学青年学者杰出研究奖，香港高等研究院材料科学明日之星，伦敦帝国理工学院校长奖学金和安妮·索恩博士论文奖，英国皇家学会国际交流奖，纳米研究杂志青年创新奖，亚太经合组织创新、研究与教育科学奖香港唯一代表，山西省科学技术二等奖，以及深圳市国家级科技项目先进个人。他是美国光学学会高级会员，英国物理学会和国际光电工程学会会员，科技部国家科技专家，目前担任Light: Science & Applications杂志编辑部香港办公室负责人，Frontiers in Photonics杂志Associate Editor，以及多个杂志的编委，包括Journal of Applied Physics,Journal of Semiconductors, Materials Today Energy, Journal of Physics Communications, Advanced Photonics Nexus,Acta Physica Sinica, Chinese Physics B, Journal of Light Scattering, andNano Materials Science.
报告摘要:
In general, symmetric plasmonic nanocavities, such as a pair of two closely spaced metal nanospheres of the same size and constituting material, support only bright modes (with a net dipole moment) under light illumination. Breaking the cavity symmetry introduces mode hybridization between its bright and dark modes, leading to new fascinating plasmon modes like Fano resonance.
In this talk, I will go on to discuss three “dark” aspects of symmetry-broken plasmonic nanocavities, namely 1) light-induced electromagnetic asymmetry, 2) plasmon-induced optical magnetism and 3) cavity-assisted brightening of spin-forbidden dark excitons. I will unravel the long hidden nonlinear electromagnetic asymmetry that is lighted up in an extremely asymmetric plasmonic nanoparticle-on-mirror (NPoM) cavity and its fundamental implication for enhancing the surface second-harmonic generation (SHG) of noble metals and even in high-index dielectric nanoantennas beyond the conventional enhancement mechanisms such as spatial and spectral mode matching. Then, I will show that plasmonic near-field coupling in an asymmetric nanoparticle dimer-on-mirror cavity induces a strong in-plane magnetic dipolar resonance and discuss its theoretical consequence as a new nonlinear SH source. I will finally demonstrate that coupling the asymmetric NPoM cavity with the quantum mechanically spin-forbidden dark excitons in monolayer transition metal dichalcogenides results in plasmon-induced resonant emission with signal intensity comparable to that of the spin-allowed bright excitons, providing a room-temperature cavity paradigm for further understanding and manipulating the coherence and density dynamics of dark excitons and potentially paving the road for employing dark excitons in quantum computing and nanoscale optoelectronics.
References:
[1]G.-C. Li et al., “Light-induced electromagnetic asymmetry for enhancing second-harmonic generation from an ultrathin plasmonic nanocavity,” Nature Communications 12, 4326 (2021).
[2]Y. J. Meng et al., “Plasmon-induced optical magnetism in an ultrathin metal-nanosphere-based dimer-on-film nanocavity”, Laser & Photonics Reviews 14(9), 200068 (2020).
[3]T. W. Lo et al., Plasmonic nanocavity induced coupling and boost of dark excitons in monolayer WSe2at room temperature, Nano Letters 22(5), 1915-1921 (2022).
