Towards quantum plasmonics: excitation of 2D plasmons via coupling with quantum dots and 2D materials

走向量子等离子体：通过与量子点和二维材料的耦合来激发二维等离子体。光子和等离子体准粒子之间的相互作用被用于等离子体领域，以跨表面传播信息，限制和引导光，并利用表面等离子激元(SPP)进行量子计算。低维电子气中的集体激发，即所谓的片状等离子体，分别在真正的纳米尺度上提供从太赫兹到光学区域的可调能量和波长，因此是有希望的。然而，与成熟的表面等离子体激元领域相比，为了耦合光和激发片状等离子体激元准粒子，新的概念是必须的。在这个方案中，我们将研究低维电子气的片状等离子体与其他振子耦合的相互作用。其中，金属和半导体量子点以及二维材料(TMDCs，分子层)被用来在真正的纳米尺度上研究等离子体-等离子体和等离子体-激子激发。借助于外延石墨烯，提供了一个准理想的2D电子气系统(2DEG)，详细研究了电子和光子辅助激发下的不同相互作用方案。此外，外延石墨烯的化学灵活性使我们能够使用各种功能化方案，例如，从液体中吸附量子点，在真空中吸附分子，生长2D材料和插入金属。利用高分辨率电子能量损失谱和扫描近场光学显微镜，研究了互易空间和真实空间中等离子体激元的耦合和放大。这些实验辅以(多尖端)扫描隧道显微镜，以控制原子规模，电荷转移，并在纳米尺度上进行光电子能量转换实验。

Towards quantum plasmonics: excitation of 2D plasmons via coupling with quantum dots and 2D materialsThe mutual interplay between photons and plasmon quasiparticles is used in the field of plasmonics to propagate information across surfaces, confine and guide light and use surface plasmon polaritons (SPP) for quantum computing. Collective excitations in low dimensional electron gases, so-called sheet plasmons, provide tunable energies and wavelengths from the THz to the optical regime on a truly nanometer scale, respectively, and are therefore promising. However, compared to the well-established field of SPPs, new concepts are mandatory in order to couple light and to excite sheet-plasmon-polariton quasiparticles.In this proposal, we will study the interaction of sheet plasmons of low dimensional electron gases coupled to other oscillators. Among others, metallic and semiconducting quantum dots (QDs), as well as 2D materials (TMDCs, molecular layers) are used to study plasmon-plasmon and plasmon-exciton excitations on a true nanometer scale. By means of epitaxial graphene, providing a quasi-perfect 2D electron gas system (2DEG), the different interaction schemes are studied in detail by both electron- and photon-assisted excitations. Moreover, the chemical flexibility of epitaxial graphene enable us to use various functionalization schemes, e.g., adsorption of QDs from the liquid phase, adsorption of molecules in vacuum, growth of 2D materials and intercalation of metals. Using high resolution electron energy loss spectroscopy and scanning near-field optical microscopy the coupling and amplification of plasmons is studied in reciprocal and real space. The experiments are supplemented by (multi-tip) scanning tunneling microscopy to control the atomic scale, charge transfer and perform opto-electronic energy conversion experiments on the nanoscale.