We demonstrate and characterize an optical control of the plasmonic heat delivered by a monolayer substrate of gold nanoparticles, obtained by modulating the effective refractive index of the neighboring dielectric medium. The effect, which exploits the dependence of the nematic liquid crystal (NLC) refractive index on the molecular director orientation, is realized by using a polarization dependent, light-induced molecular reorientation of a thin film of photo-alignment layer that the NLC is in contact with. For a suitable alignment, plasmonic pumping intensity values ranging from 0.25 W/cm2to 6.30 W/cm2can induce up to 17.4 °C temperature variations in time intervals of the order of seconds. The reversibility of the optically induced NLC molecular director orientation enables an active control of the plasmonic photo-induced heat.

Optical control of plasmonic heating effects using reversible photo-alignment of nematic liquid crystals

PALERMO, GIOVANNA
Membro del Collaboration Group
;
Cataldi, Ugo
Membro del Collaboration Group
;
De Sio, Luciano
Membro del Collaboration Group
;
Umeton, Cesare
Membro del Collaboration Group
2016-01-01

Abstract

We demonstrate and characterize an optical control of the plasmonic heat delivered by a monolayer substrate of gold nanoparticles, obtained by modulating the effective refractive index of the neighboring dielectric medium. The effect, which exploits the dependence of the nematic liquid crystal (NLC) refractive index on the molecular director orientation, is realized by using a polarization dependent, light-induced molecular reorientation of a thin film of photo-alignment layer that the NLC is in contact with. For a suitable alignment, plasmonic pumping intensity values ranging from 0.25 W/cm2to 6.30 W/cm2can induce up to 17.4 °C temperature variations in time intervals of the order of seconds. The reversibility of the optically induced NLC molecular director orientation enables an active control of the plasmonic photo-induced heat.
2016
Physics
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11770/277746
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