Photonics of metallic nanostructures : active plasmonics and chiral effects
Photonics of metallic nanostructures : active plasmonics and chiral effects
We propose a new concept of switching surface plasmon-polariton (SPP) signals (“active plasmonics”). The concept relies on changing the propagation characteristics of the SPP waveguide via a structural transformation in the material of the whole waveguide or a section. The switchable material should have two states with distinctly different electromagnetic properties and allow a controllable and reversible transition between them, that can be stimulated by external excitation.
We undertook rigorous numerical simulation of “active plasmonics” switching using the example of a SPP waveguide, a section of which is made of metallic gallium. We investigated how the switching between the semiconductor-like a-phase and the metallic-like liquid phase of gallium changes the transmission characteristics of the waveguide. We found that a gallium section of just a few micrometres in length provides a very efficient modulation of the SPP wave in a broad interval of wavelengths from 900 nm to 2 µm. Structural transformation of just a 30 nm layer of gallium is sufficient for a manifold modulation of the SPP transmission. As part of the development of the active plasmonic concept, we numerically investigated and optimized the efficiency of coupling and decoupling of SPP waves by a rectangular grating engraved in the waveguide for a variety of grating geometrical profiles.
We experimentally demonstrated for the first time that phase transition in the SPP waveguide might be used to modulate the efficiency of coupling of light into SPPs. This was performed in the Otto prism configuration using a 680 nm CW diode “probe” laser and a 1064 nm Nd:YAG impulse “pump” laser. We found that when using gallium in the waveguide efficient modulation of the light-SPP coupling can be achieved with 6 ns pulses with pump fluence of about 10 mJ/cm2, and that the transient switching time of the modulation process is of the order of a few tens of nanoseconds.
We proposed, manufactured and investigated a new optically broad-band nano-structured material for active plasmonic devices and nonlinear optics applications. The material is created by grain boundary penetration of liquid gallium into the aluminium domain network. In the new material we observed a strong nonlinear response initiated by impulse of a 1064 nm Nd:YAG laser with fluence of just ~1 mJ/cm2.
For the first time we studied the transmission of circularly polarized light through a small chiral hole in a metallic screen and discovered that transmission is enantiomericly sensitive. Both intensity maps and polarization state of the transmitted light dramatically depend on the mutual handedness of the light’s polarization and the twist of the gammadion-shaped opening. We also found a polarization-controlled nano-focusing effect and a significant polarization conversion effect. The polarization conversion was found to peak at the illuminating wavelength close to the hole’s size.
University of Southampton
Krasavin, Alexey Victorovich
2006
Krasavin, Alexey Victorovich
Krasavin, Alexey Victorovich
(2006)
Photonics of metallic nanostructures : active plasmonics and chiral effects.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
We propose a new concept of switching surface plasmon-polariton (SPP) signals (“active plasmonics”). The concept relies on changing the propagation characteristics of the SPP waveguide via a structural transformation in the material of the whole waveguide or a section. The switchable material should have two states with distinctly different electromagnetic properties and allow a controllable and reversible transition between them, that can be stimulated by external excitation.
We undertook rigorous numerical simulation of “active plasmonics” switching using the example of a SPP waveguide, a section of which is made of metallic gallium. We investigated how the switching between the semiconductor-like a-phase and the metallic-like liquid phase of gallium changes the transmission characteristics of the waveguide. We found that a gallium section of just a few micrometres in length provides a very efficient modulation of the SPP wave in a broad interval of wavelengths from 900 nm to 2 µm. Structural transformation of just a 30 nm layer of gallium is sufficient for a manifold modulation of the SPP transmission. As part of the development of the active plasmonic concept, we numerically investigated and optimized the efficiency of coupling and decoupling of SPP waves by a rectangular grating engraved in the waveguide for a variety of grating geometrical profiles.
We experimentally demonstrated for the first time that phase transition in the SPP waveguide might be used to modulate the efficiency of coupling of light into SPPs. This was performed in the Otto prism configuration using a 680 nm CW diode “probe” laser and a 1064 nm Nd:YAG impulse “pump” laser. We found that when using gallium in the waveguide efficient modulation of the light-SPP coupling can be achieved with 6 ns pulses with pump fluence of about 10 mJ/cm2, and that the transient switching time of the modulation process is of the order of a few tens of nanoseconds.
We proposed, manufactured and investigated a new optically broad-band nano-structured material for active plasmonic devices and nonlinear optics applications. The material is created by grain boundary penetration of liquid gallium into the aluminium domain network. In the new material we observed a strong nonlinear response initiated by impulse of a 1064 nm Nd:YAG laser with fluence of just ~1 mJ/cm2.
For the first time we studied the transmission of circularly polarized light through a small chiral hole in a metallic screen and discovered that transmission is enantiomericly sensitive. Both intensity maps and polarization state of the transmitted light dramatically depend on the mutual handedness of the light’s polarization and the twist of the gammadion-shaped opening. We also found a polarization-controlled nano-focusing effect and a significant polarization conversion effect. The polarization conversion was found to peak at the illuminating wavelength close to the hole’s size.
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Published date: 2006
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Local EPrints ID: 465993
URI: http://eprints.soton.ac.uk/id/eprint/465993
PURE UUID: c8c13e27-3ab1-463f-a4e3-ac0d741f805e
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Date deposited: 05 Jul 2022 03:55
Last modified: 05 Jul 2022 03:55
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Author:
Alexey Victorovich Krasavin
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