Wednesday 22 November 2017
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Plasmonic metamaterials: A study of linear and nonlinear response of metal nanostructures

In the past ten years, a new class of materials has emerged and it has attracted a lot of attention due to its counterintuitive optical behavior and revolutionary potential applications – metamaterials. Metamaterials are materials engineered for displaying unusual electromagnetic properties and they have been associated with negative refractive index [1, 2], invisibility [3], light-based nanocircuits [4-6], etc. Most of these spectacular phenomena are based on surface plasmon resonances – the property whereby, in metallic nanostructures, light can collectively excite the electron population at surfaces. We in our work have exploited this phenomenon both in linear and nonlinear regime, resulting in some fascinating results. We have shown that, upon illuminating nanostructures, the resulting surface plasmon pattern is imprinted on the structures themselves allowing for subsequent imaging with Scanning Electron Microscopy and Atomic Force Microscopy (AFM). The resulting resolution of plasmon pattern imaging can therefore, in principle, be brought down to that of the AFM. Our results open a new avenue for studying plasmonic patterns at the nanoscale [7]. We also show how using surface plasmon we can induce higher order magnetic moments in non magnetic materials and create a magneto-inductive waveguide.

 

References

[1] Veselago, V.G., “The Electrodynamics of Substances with Simultaneously Negative values of e and m ”. Sov. Phys. Usp., 10, 4, 509 (1968).

[2] Smith, R.D., Pendry, J.B. & Wiltshire, M.C.K., “Metamaterials and Negative Refractive Index”. Science, 305, 788 (2004).

[3] Schurig, D., et al. “Metamaterial Electromagnetic Cloak at Microwave Frequencies”. Science, 314, 977 (2006).

[4] Engheta, N., Salandrino, A. & Alù, A., “Circuit Elements at Optical Frequencies: Nanoinductors, Nanocapacitors, and
Nanoresistors”. Phys. Rev. Lett., 95, 095504 (2005).

[5] Engheta, N. “Circuits with Light at Nanoscales: Optical Nanocircuits Inspired by Metamaterials”. Science, 317, 1698 (2007).

[6] Walther, C., et al. “Microcavity Laser Oscillating in a Circuit-Based Resonator”. Science, 327, 1495 (2010).

[7] V. K. Valev,et al. “Hotspot Decorations map plasmonic patterns with the resolution of scanning probe techniques”, Phys. Rev. Lett.,
in press (2011).