Electric field induced structural colour tuning of a silver/titanium dioxide nanoparticle one-dimensional photonic crystal

Abstract

SummaryAn electric field is employed for the active tuning of the structural colour in photonic crystals, which acts as an effective external stimulus with an impact on light transmission manipulation. In this work, we demonstrate structural colour in a photonic crystal device comprised of alternating layers of silver nanoparticles and titanium dioxide nanoparticles, exhibiting spectral shifts of around 10 nm for an applied voltage of only 10 V. The accumulation of charge at the metal/dielectric interface with an applied electric field leads to an effective increase of the charges contributing to the plasma frequency in silver. This initiates a blue shift of the silver plasmon band with a simultaneous blue shift of the photonic band gap as a result of the change in the silver dielectric function (i.e. decrease of the effective refractive index). These results are the first demonstration of active colour tuning in silver/titanium dioxide nanoparticle-based photonic crystals and open the route to metal/dielectric-based photonic crystals as electro-optic switches.

Optical properties of periodic, quasi-periodic, and disordered one-dimensional photonic structures

“…'With' a'liquid'crystal'based'1D'porous'photonic'crystal'a'shift'of'the'photonic'band'gap'of'8'nm'with' the'application'of'a'8'V'external'voltage'has'been'reported' [149]. 'A'similar'performance'has' been' shown' with' a' Ag' nanoparticle' /' TiO2' nanoparticle' 1D' photonic' crystal' upon' external' voltage' [150].' A' very' exhaustive' review' on' electrically' responsive' photonic' crystals,' with' many' 1D' examples,'have'been'published'by'Nucara'et'al.'…”

Electro-optic and magneto-optic photonic devices based on multilayer photonic structures

“…, with N number of carriers, e the electron charge, m * the effective mass and ε 0 the vacuum permittivity. By employing the Drude model and the Maxwell-Garnett effective medium approximation to determine the refractive index of the silver nanoparticle layersand we use this refractive index in the transfer matrix theory, we can fit the blue shift of the photonic band gap, finding a good agreement between the experiment and the suggested model15 .…”

“…Optical characterization: The experimental setups to perform the electric field dependent light transmission for the liquid crystal infiltrated photonic crystal and for the silver/titania photonic crystal are reported in Refs. 13,15 The light transmission spectra of the ITO/titania photonic crystals have been recorded with a Perkin Elmer spectrophotometer Lambda 1050 WB.…”

Hybrid plasmonic/photonic crystals for optical detection of bacterial contaminants

“…In this context, we have recently proposed porous 1D photonic structures exhibiting electro-optical tunability, due to the incorporation of optoelectronically-active plasmonic nanoparticles in the photonic structures. [4][5][6] Here, we show that a hybrid plasmonic/photonic crystal consisting of a thin layer of bioactive plasmonic material (i.e. silver) deposited on top a 1D PhC can detect one of the most common bacterial contaminant, namely Escherichia coli.…”