科学研究

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【学术活动】超分辨显微镜下的分子间相干偶极耦合

Title: INVESTIGATING COHERENT INTERMOLECULAR DIPOLE-DIPOLE COUPLING WITH SUB-NANOMETER RESOLVED SPECTROSCOPIC IMAGING

Speaker: Yang Zhang (张杨)
Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China

Host: Associate Professor. Hui Dong(董辉)

 

Date&Time: September 26, 2017 (Tuesday)  15:00~16:00

Venue: A403 Meeting Room, 4th Floor
(中物院研究生院软件园校区4A403教室,海淀区西北旺东路10号院东区9号楼)

Abstract: The tunneling electrons in a scanning tunneling microscope (STM) can not only be used to image and manipulate surface nanostructures with atomic resolution, but also excite light emission from STM junctions by inelastic tunneling electrons. STM induced luminescence (STML) technique, combining the STM with optical detection, can do nano-imaging beyond diffraction limit, which provide photon images with spatial resolution down to sub-nanometer scale.

    In this talk, I shall first present the realization of molecule-specific electroluminescence from a well-defined isolated single molecule and the sub-nanometer resolved spectroscopic imaging with STML. Then, with STM manipulation, artificial molecular structures can be constructed. I shall demonstrate the real-space visualization of coherent intermolecular dipole-dipole coupling for constructed molecular oligomers through molecular electroluminescence imaging. The spatial distributions of the excitonic coupling for different energy states indicate that the behavior of the coherent dipole-dipole coupling well resembles the σ and π orbitals in a molecule, revealing the local optical responses and their correlations with transition dipole orientations and phase relations. With the knowledge thus gained, electrically driven single photon superradiance from an entangled system of well-defined molecular oligomers is achieved. These results not only substantially deepen the understanding on the coherent excitonic coupling in molecular systems, but also enable to engineer electrically driven single-molecule superradiance and even quantum photon sources from entangled molecular architectures.

 

Biography: 张杨,中国科学技术大学特任教授,博士生导师。2016年入选国家自然科学基金委优秀青年基金人才支持计划。近年来一直致力于发展与光学检测相结合的扫描探针技术,对单分子等纳米结构的光电特性进行超高空间分辨的表征。研究工作特色在于针对单分子光电现象研究中的关键科学问题,自主发展超高空间分辨的表征方法;随后,利用自主发展的新方法与新设备,获得对分子光电行为以及分子之间相互作用的新认识,进而推动对科学问题的理解。在2016年,与合作者一起,发展了具有亚纳米空间分辨的电致荧光成像技术,在国际上首次在单分子水平上展示了分子间相干偶极耦合的实空间光学特征(Nature 2016)。该工作开辟了研究分子间相互作用和能量转移的新途径,同时也为光合作用中分子捕光结构的优化和分子纠缠体系及其光源的调控提供了新的思路。

 

All interested are welcome!