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Plasmonics and nanophotonics I

11:00 : The unified lasing conditions for SPASER

V. Pustovit (1),A. Chipouline (2),T. V. Shahbazyan (3),A. M. Urbas (1)

(1)Air Force Research Laboratory (USA) , (2)Friedrich Schiller University Jena (Germany) , (3)Jackson State University (USA)

We here presents the first unified theory of the response of plasmonic nanoshells assisted by optical gain media. We derive a fundamental equation for calculation of SPASER frequency which we claim to be valid for any type of SPASER physical geometry. We demonstrate that cooperative energy exchange between SPASER modes provide a mechanism that is responsible for the spasing and loss compensation process in the laser resonator.
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11:15 : Extremely confined gap surface-plasmon modes probed by electron energy-loss spectroscopy (EELS)

Soren Raza, Sergey Bozhevolnyi

University of Southern Denmark (Denmark)

Applying EELS to ultra-sharp convex grooves in gold, we directly probe extremely confined gap surface-plasmon (GSP) modes excited by swift electrons in nanometer-wide gaps. We reveal the resonance behavior associated with the excitation of the antisymmetric GSP mode for extremely small gap widths, down to approximately 5 nm. We argue that excitation of this mode, featuring very strong absorption, has a crucial role in experimental realizations of non-resonant light absorption by ultra-sharp convex grooves with fabrication-induced asymmetry.
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11:30 : Plasmonic nanostructures combined with integrated nano-fiber

Kazuhiro Yamamoto (1),Kenzo Yamaguchi (2),Shiyoshi Yokoyama (1),Akira Otomo (3)

(1)Kyushu University (Japan) , (2)Kagawa University (Japan) , (3)National Institute of Information and Communications Technology (Japan)

Plasmonic nano-structures show diverse optical functions due to their locality and field enhancement. For effective use of plasmonic nanostructures, efficient excitation, detection and modulation systems are needed. Recently, we proposed the integrated tapered optical nano-fiber structures on substrate for such plasmonic applications. The nano-fiber structures are fabricated using focused ion beam milling and wet etching. In this presentation, we report the numerical analysis and experimental results of these nano-fiber applications for plasmon superfocusing and propagation mode control.
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11:45 : Multiplexing Raman Imaging of individual Au Nanobridged Nanogap Particles(Au-NNP) inside a Single Live Cell

Yung Doug Suh

Korea Research Inst. of Chemical Technology (Korea)

Gold NNP(Nanobridged Nanogap Particle)-based multiplexing Raman imaging experiment within a single live cell toward drug screening application of Raman nanoscopy will be presented. Internal nanogap on the order of 1 nm or less plays key role to enhance Raman signal of this Au-NNPs. We could observe trajectories of individual Au-NNPs with different spectra inside a single live cell.
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12:00 : Nonequilibrium Plasmons with Gain in Photo-inverted Graphene

Joachim Hamm, Adam Page, Fouad Ballout, Ortwin Hess

Imperial College London (United Kingdom)

Graphene supports TM-polarized plasmons in the THz to mid-IR regime. When pumped into inversion these plasmons couple strongly to the electron/hole plasma via stimulated and spontaneous emission processes. We here present the exact (complex-frequency) dispersion of nonequilibrium plasmons and extract the associated stimulated and spontaneous emission rates. Our results show that graphene plasmons can become amplified under realistic conditions (temperature and collision loss) and provide an ultrafast channel for carrier recombination.
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12:15 : Investigation of Hot Electron Photoelectric Conversion Based on Nanospikes Array Metasurface

Zhiyang Qi, Qilong Wang, Yusheng Zhai, Ji Xu, Yan Tu

Southeast University (China)

We investigate hot electron photoelectric conversion based on nanospikes array metasurface nanostructures. The proposed structures consist of heavily doped silicon and ultrathin gold films deposited on nanospikes substrate. Well design features of this plasmonic nanostructure including large localized field enhancement, high absorptivity, broad-band and wide-angel. The spectral bandwidth and photoresponsivity can be manipulated through engingeering the geometric parameter of the metasurface structure.
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