Graphene Nanoribbon Plasmonic Conveyor Belt Network for Optical Trapping and Transportation of Nanoparticles
Graphene Nanoribbon Plasmonic Conveyor Belt Network for Optical Trapping and Transportation of Nanoparticles
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DOI：
10.1021/acsphotonics.0c01353
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发表时间：
2020-12
期刊：
影响因子：
7
通讯作者：
P. Liu;Puspita Paul
中科院分区：
文献类型：
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作者：
P. Liu;Puspita Paul
基于金属等离子体结构的光镊可以实现深亚波长尺度物体的稳定捕获。然而，由于金属等离子体结构缺乏实时可调性，操纵被困物体具有挑战性，通常需要对激发光源进行复杂的调谐，这限制了等离子体镊子的应用范围。在这里，我们提出了一个二维（2D）等离子体传送带网络的工作原理并分析了其性能，该网络采用电可调谐石墨烯等离子体结构，可以同时独立地捕获和传输多个纳米颗粒到网络中的任意目标位置。在不改变激发光源的情况下，通过一组后门，动态地重新配置基于石墨烯纳米带的网络结构中的载流子密度分布，实现了纳米颗粒的传输。数值分析表明，在中等激发源强度（例如1 mW/μm2）下，具有数十nm特征尺寸的纳米粒子可产生较大的光力，其捕获势能超过10kbat室温，从而保证了纳米粒子操作过程中的稳定捕获。在此基础上，对网络中的结结构进行了适当的设计，并提出了纳米粒子在这些结处的全方位路由的有效方案，并进行了定量分析。这种基于石墨烯的等离子体传送带网络具有很高的设计灵活性和系统可扩展性，因此可以在芯片实验室、组装复杂纳米结构和器件、研究多体物理和推进量子信息技术等不同领域找到广泛的应用。
Optical tweezers based on metallic plasmonic structures can achieve stable trapping of objects with deep subwavelength dimensions. However, due to the lack of real-time tunability of metallic plasmonic structures, manipulating trapped objects is challenging and usually requires sophisticated tuning of the excitation light source, which limits the application scope of such plasmonic tweezers. Here, we propose the operation principle and analyze the performance of a two-dimensional (2D) network of plasmonic conveyor belts employing electrically tunable graphene plasmonic structures, which can simultaneously and independently trap and transport multiple nanoparticles to arbitrary target locations within the network. Transportation of nanoparticles is achieved by dynamically reconfiguring the carrier density distribution in a graphene nanoribbon based network structure using an array of back-gates, without a need for any change to the excitation light source. Our numerical analyses show that relatively large optical forces can be induced on nanoparticles with tens of nm characteristic dimensions at a moderate excitation source intensity (e.g., 1 mW/μm2), and the corresponding trapping potential energy exceeds 10kBTat room temperature, which guarantees stable trapping during nanoparticle manipulation. Suitable designs of the junction structures in the network are developed, and effective schemes for all-directional routing of nanoparticles at these junctions are proposed and quantitatively analyzed. Such graphene-based plasmonic conveyor belt networks have high design flexibility and system scalability and, therefore, may find a wide range of applications in different areas such as lab-on-a-chip, assembling complex nanostructures and devices, studying many-body physics, and advancing quantum information technologies.