Electromagnetic fields near plasmonic wedges

Disfani, Majid Rasouli; Abrishamian, Mohammad Sadegh; Berini, Pierre

doi:10.1364/ol.37.001667

Cited by 4 publications

(1 citation statement)

References 20 publications

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“…Such quantification relies on the best observed performance and is sample dependent. More fundamentally, it is well-known that the electromagnetic fields diverge at sharp (subwavelength) corners even in non-resonant scatterers [29,30]. Therefore, such quantifications are inaccurate since local geometric irregularities, which are often random and unintended, due to material and fabrication defects, significantly contribute to the so-called enhancement factor.…”

Section: Resultsmentioning

confidence: 99%

Enhanced Raman scattering in graphene by plasmonic resonant Stokes emission

Ghamsari¹,

Olivieri²,

Variola³

et al. 2014

Nanophotonics

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Exploiting surface plasmon polaritons to enhance interactions between graphene and light has recently attracted much interest. In particular, nonlinear optical processes in graphene can be dramatically enhanced and controlled by plasmonic nanostructures. This work demonstrates Raman scattering enhancement in graphene based on plasmonic resonant enhancement of the Stokes emission, and compares this mechanism with the conventional Raman enhancement by resonant pump absorption. Arrays of optical nanoantennas with different resonant frequency are utilized to independently identify the effects of each mechanism on Raman scattering in graphene via the measured enhancement factor and its spectral linewidth. We demonstrate that, while both mechanisms offer large enhancement factors (scattering cross-section gains of 160 and 20 for individual nanoantennas, respectively), they affect the graphene Raman spectrum quite differently. Our results provide a benchmark to assess and quantify the role and merit of each mechanism in surface-plasmon-mediated Raman scattering in graphene, and may be employed for design and realization of a variety of graphene optoelectronic devices involving nonlinear optical processes.

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Section: Resultsmentioning

confidence: 99%

Enhanced Raman scattering in graphene by plasmonic resonant Stokes emission

Ghamsari¹,

Olivieri²,

Variola³

et al. 2014

Nanophotonics

Self Cite

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Photonic confinement in laterally structured metal-organic microcavities

Mischok

Bruckner

Sūdžius

et al. 2014

Applied Physics Letters

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We investigate the formation of optical modes in organic microcavities with an incorporated perforated silver layer. The metal leads to a formation of Tamm-plasmon-polaritons and thus separates the sample into metal-free or metal-containing areas, supporting different resonances. This mode splitting is exploited to confine photons in elliptic holes and triangular cuts, forming distinctive standing wave patterns showing the strong lateral confinement. A comparison with a Maxwell-Bloch based rate equation model clearly shows the nonlinear transition into the lasing regime. The concentration of the electric field density and inhibition of lateral loss channels in turn decreases the lasing threshold by up to one order of magnitude, to 0.1 nJ. By spectroscopic investigation of such a triangular wedge, we observe the transition from the unperturbed cavity state to a strongly confined complex transversal mode. Such a structured silver layer can be utilized in future for charge carrier injection in an electrically driven organic solid state laser.

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Calculating corner singularities by boundary integral equations

Shi

2017

J. Opt. Soc. Am. A

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Accurate numerical solutions for electromagnetic fields near sharp corners and edges are important for nanophotonics applications that rely on strong near fields to enhance light-matter interactions. For cylindrical structures, the singularity exponents of electromagnetic fields near sharp edges can be solved analytically, but in general the actual fields can only be calculated numerically. In this paper, we use a boundary integral equation method to compute electromagnetic fields near sharp edges, and construct the leading terms in asymptotic expansions based on numerical solutions. Our integral equations are formulated for rescaled unknown functions to avoid unbounded field components, and are discretized with a graded mesh and properly chosen quadrature schemes. The numerically found singularity exponents agree well with the exact values in all the test cases presented here, indicating that the numerical solutions are accurate.

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Electromagnetic fields near plasmonic wedges

Cited by 4 publications

References 20 publications

Enhanced Raman scattering in graphene by plasmonic resonant Stokes emission

Enhanced Raman scattering in graphene by plasmonic resonant Stokes emission

Photonic confinement in laterally structured metal-organic microcavities

Calculating corner singularities by boundary integral equations

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