Engineering Quantum Sensors Exploiting Rabi Splitting in Plexcitonic Nanoparticle Assemblies

基于单原子发射体耦合到谐振腔的量子技术需要低温，并表现出脆弱的光-物质耦合。基于强等离子体-激子耦合的多激子谐振器在室温下表现出较大的拉比分裂，表明强耦合。初步结果表明，由有机j聚集体与金纳米岛耦合组成的多激子体系中的Rabi分裂对环境湿度高度敏感。虽然金属有欧姆损耗，但等离子体局部场增强补偿了这些损耗并实现了强耦合。因此，我们观察到的传感动作具有鲁棒性和可重复性。这促使我们进一步改进和优化量子多激子传感器，通过减少能量耗散来延长退相干时间尺度。在这个方向上的另一个步骤是通过控制纳米制造过程中的粒子间距，从银/金纳米立方体和纳米棱镜形成等离子体分子（二聚体和三聚体）。这样的等离子体分子有望表现出戏剧性的局部场增强，这有助于灵敏度和促进强耦合。本项目还旨在通过稳态和时间分辨光致发光光谱和成像测量多激子谐振器的亚辐射/超辐射行为。这是一个合作项目，涉及加拿大埃德蒙顿阿尔伯塔大学半导体纳米材料与器件的Shankar小组和印度浦那IISER-Pune量子光电器件的Shouvik Datta小组。该项目将利用Datta集团在测量发射光子的时空相干性方面的专业知识，以更深入地了解多激子量子系统。Plexcitons将为创造和操纵接近室温的纠缠态提供新的途径，由此产生的Rabi分裂很容易通过电、热、化学或光学刺激来调节。本项目旨在解决非低温光子量子技术的关键需求。

Demonstrated quantum technologies based on single atomic emitters coupled to resonant cavities require cryogenic temperatures and exhibit fragile light-matter coupling. Plexcitonic resonators based on strong plasmon-exciton coupling exhibit a large Rabi splitting at room temperature in the solid-state indicative of strong coupling. Preliminary results indicate that the Rabi splitting in a plexcitonic system consisting of organic J-aggregates coupled to gold nanoislands is highly sensitive to ambient humidity. Although metals have Ohmic losses, the plasmonic local field enhancement compensates for these losses and enables strong coupling. Consequently, the sensing action observed by us is robust and reproducible. This motivated us to further improve and optimize the quantum plexcitonic sensor through extending the decoherence timescales by reducing energy dissipation. Another step in this direction involves forming plasmonic molecules (dimers and trimers) from Ag/Au nanocubes and nanoprisms through control of the inter-particle spacing during nanofabrication. Such plasmonic molecules are expected to exhibit a dramatic local field enhancement, which aids sensitivity and facilitates strong coupling. This project also aims to measure the subradiance/superradiance behavior of plexcitonic resonators through steady-state and time-resolved photoluminescence spectroscopy and imaging. This is a collaborative project involving the Shankar Group in Semiconductor Nanomaterials & Devices at the University of Alberta in Edmonton, Canada and the Shouvik Datta Group in Quantum Optoelectronic Devices at IISER-Pune, India. This project will leverage the Datta Group's expertise in measuring spatio-temporal coherence of emitted photons to achieve a deeper understanding of the plexcitonic quantum system. Plexcitons will provide a new avenue to create and manipulate entangled states close to room temperature, with the resulting Rabi splitting easily tunable by electrical, thermal, chemical or optical stimuli. This project aims to address the critical need for non-cryogenic photonic quantum technologies.