Metal-dielectric Heterostructures Research Articles

Large-area metal-dielectric heterostructures for surface-enhanced raman scattering

Metal-dielectric heterostructures have shown great application potentials in physics, chemistry and material science. In this work, we have designed and manufactured ordered metal-dielectric multiple heterostructures with tunable optical properties, which can be as large as the order of square centimeters in size. We experimentally realized that the surface-enhanced Raman scattering signal of the periodic multiple heterostructures increased 50 times compared with the silicon nanodisk-gold film arrays, which is attributed to the large-scale hotspots and high efficient coupling between the optical cavities and surface plasmon resonance modes. More importantly, the substrate also features a good uniformity and an excellent reproducible fabrication, which is very promising for practical applications.

Extremely narrow resonant linewidths in metal-dielectric heterostructures

Plasmonic high-quality factor resonators with narrow surface plasmon resonance (SPR) linewidths are extremely significant for surface-enhanced Raman scattering, optical sensors, imaging, and color filters. Unfortunately, extensive research on narrowing SPR linewidths is mainly based on noble metal nanostructures that are restricted by intrinsic loss. Here, heterostructures consisting of metal and dielectric metaphotonics are experimentally designed and fabricated for elaborating SPR linewidths. The results demonstrate that the SPR linewidths can be narrowed by 66.7% relative to that of aluminum nanostructures. The resonant linewidths are directly shrunk due to the interaction between low loss in the semiconductor nanostructures and electromagnetic confinement in the metal counterparts. Meanwhile, the resonant wavelength governed by heterostructure configurations shifts from 600 to 930 nm. This work will pave an avenue toward controlling resonant linewidths of metal-dielectric heterostructures for numerous applications.

Design and Analysis of GO Coated High Sensitive Tunable SPR Sensor for OATR Spectroscopic Biosensing Applications

In this paper, we numerically debrief an ultra-high sensitive surface plasmon resonance (SPR) biosensor utilizing thin layers of graphene oxide (GO) that have not been addressed adequately till now. By the deposition of GO on top of the metal-dielectric heterostructure, our proposed sensor can achieve higher sensitivity and higher Quality Factor (QF) simultaneously which has not been possible by the existing models to our knowledge. Because of its large surface area and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sp</i> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> inside of an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sp</i> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> matrix which is capable of confining π electrons, GO can form strong covalent bonds with biomolecules and hence enhanced light-material interaction that made researchers contemplate to achieve increased sensitivity and figure of merit. Both the transfer matrix method and finite element method are exploited to perform extensive numerical analysis for optimizing the structure considering its sensitivity, full width half maximum (FWHM), and QF. This paper examines six different configurations of multilayer heterostructure containing prism-adhesive-metal-BaTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /BP-Gr/GO/MXene-sensing medium, and a noticeably enhanced performance is achieved using GO with a maximum sensitivity of 372 deg/RIU and QF of 88.11 RIU <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> in the range of refractive index (RI) 1.330 to 1.353. Moreover, the possibility of designing a tunable SPR sensor to operate at a broader range of analyte’s RI is investigated, and 414 deg/RIU with 119.27 RIU <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> QF at 1.407 RI is achieved. The Electric field distribution, effects of different layers, and fabrication feasibility of the proposed sensor are explored, it is envisaged that this can be an appropriate apparatus for highly sensitive, rapid, and noninvasive label-free biosensing useful in experimental sensing protocols.

Ultrafast transport and relaxation of hot plasmonic electrons in metal-dielectric heterostructures

We analyze ultrafast electron dynamics in the time domain upon optical excitation of propagating surface plasmon-polaritons (SPs) in metal-dielectric heterostructures. Developing a kinetic model where both local and non-local electron relaxation in metals are included, we identify relevant timescales and extend the existing non-equilibrium electron dynamics framework onto the case of collective electronic excitations. The experimental data obtained in two distinct series of pump-probe measurements (with varied pump wavelength and angle of incidence) demonstrate SP-driven, one order of magnitude enhanced efficiency of the hot electron generation and the fourfold (up to 200 fs) slowdown of their non-local relaxation at the SP resonance. We discuss the perspectives of the SP-enabled manipulation of the non-equilibrium electron population lying at the crossover of photonics and ultrafast spintronics.

Substrate phonon-mediated plasmon hybridization in coplanar graphene nanostructures for broadband plasmonic circuits.

The mode hybridization between adjacent graphene nanoribbons determines the integration density of graphene-based plasmonic devices. Here, plasmon hybridization in graphene nanostructures is demonstrated through the characterization of the coupling strength of plasmons in graphene nanoribbons as a function of charge density and inter-ribbon spacing using Fourier transform infrared microscopy. In combination with numerical simulations, it is shown that the plasmon coupling is strongly mediated by the substrate phonons. For polar substrates, the plasmon coupling strength is limited by the plasmon-phonon interactions. In contrast, a nonpolar substrate affects neither the energy distribution of the original plasmon modes in graphene nanostructures nor their plasmon interactions, which increases exponentially as the inter-ribbon spacing decreases. To further explore the potential of graphene broadband plasmonics on nonpolar substrates, a scheme is proposed that uses a metal-dielectric heterostructure to prevent the overlap of plasmons between neighboring graphene nanoribbons. The device structures retain the plasmon resonance frequency of the graphene ribbons and maximally isolate the plasmonic components from the surrounding electromagnetic environment, allowing modular design in integrated plasmonic circuits.

Design of Anodic Aluminum Oxide Rear Surface Plasmonic Heterostructures for Light Trapping in Thin Silicon Solar Cells

A metal-dielectric heterostructure that provides the combined capability of light trapping and surface passivation is reported. The light-trapping layer employs a porous aluminum anodic oxide (AAO) with metal nanoparticles formed in the pores on the rear surface of a thin crystalline silicon solar cell. Numerical finite-difference time domain (FDTD) simulations were performed to determine the pore diameter and spacing that would result in optimal light trapping for this metal-dielectric heterostructure. For a 2.5-μm-thick crystalline silicon device, the optimal pore diameter and spacing were determined to be ~250 and ~450 nm, respectively. These conditions resulted in an enhancement of the simulated photocurrent by ~12.6% compared with a device in which the heterostructure was replaced with a homogenous aluminum oxide layer. Simulations also confirmed that the thickness of an underlying dielectric layer should be minimized to 10-20 nm, with the AAO barrier layer being maintained as thin as possible. Finally, it was shown that replacement of silver by aluminum in the pores resulted in a reduction in the photocurrent of 6.3% and would necessitate much larger pore spacing that is difficult to achieve experimentally and would result in thicker AAO barrier layers, which are undesirable.

Experimental verification and investigation of disks scattering slab modes in metal-dielectric heterostructures

A thin dielectric plate can support conventional slab modes such as leaky Fabry-Perot, guided waves and radiation modes. When the plate is coated on a metallic subwavelength disk array, it can result in new confined modes, hereby named 'disks scattering slab modes' (DSSMs). By use of a terahertz time-domain spectroscopy system, we experimentally verify the existence of two types of DSSMs in terahertz range: one we refer to as highly confined disks scattering Fabry-Perot-like modes (DSFPMs) and the other as, weakly confined disks scattering radiation-like modes (DSRMs). Spectral characteristics of these confined modes are measured and numerically simulated. Particularly, based on the experimental results and a dipole-scattering model developed here, we show that the features of the DSFPMs can be tuned by changing the filling fraction of the disk array. We believe these results can make important contributions to the designs of new terahertz devices, including tunable absorbers and filters.

On surface plasmon polariton wavepacket dynamics in metal–dielectric heterostructures

The WKB equations for the dynamics of the surface plasmon polariton (SPP)wavepacket are studied. The dispersion law for the SPP in a metal–dielectricheterostructure with varying thickness of a dielectric grating is rigorously calculated andinvestigated using the scattering matrix method. Two channels of the SPP wavepacketoptical losses related to the absorption in a metal and to the SPP leakage areanalyzed. It is shown that change of the dielectric layer thickness acts on theSPP as an external force leading to evolution of its quasimomentum and to thewavepacket reversal or even to optical Bloch oscillations (BO). Properties of thesephenomena are investigated and discussed. Typical values of the BO amplitude areabout tens of microns and the period is around tens or hundreds of femtoseconds.

Optical properties of perforated metal-dielectric heterostructures magnetized in the plane

The magneto-optical properties of perforated metal-dielectric heterostructures that consist of a metal film perforated with a periodic system of slits and a dielectric layer magnetized in the plane have been investigated. The numerical simulation based on the rigorous coupled-wave analysis has revealed that, in these heterostructures, apart from the extraordinary transmission effect, there arises a magnetization-even magneto-optical effect, which manifests itself in a change in the zeroth-order transmittance due to magnetization of the sample. It has been demonstrated that, in the case of incidence of the TM-polarized wave, this effect is maximum upon excitation of quasi-waveguide modes with a dispersion law similar to the dispersion law for the TE modes of the nongyrotropic waveguide.

Bloch oscillations

Restricted accessMoreSectionsView PDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmail Cite this article Kurz Heinrich , Roskos Hartmut G. , Dekorsy Thomas and Klaus Köhler 1996Bloch oscillationsPhil. Trans. R. Soc. A.3542295–2310http://doi.org/10.1098/rsta.1996.0101SectionRestricted accessArticleBloch oscillations Heinrich Kurz Google Scholar Find this author on PubMed Search for more papers by this author , Hartmut G. Roskos Google Scholar Find this author on PubMed Search for more papers by this author , Thomas Dekorsy Google Scholar Find this author on PubMed Search for more papers by this author and Köhler Klaus Google Scholar Find this author on PubMed Search for more papers by this author Heinrich Kurz Google Scholar Find this author on PubMed Search for more papers by this author , Hartmut G. Roskos Google Scholar Find this author on PubMed Search for more papers by this author , Thomas Dekorsy Google Scholar Find this author on PubMed Search for more papers by this author and Köhler Klaus Google Scholar Find this author on PubMed Search for more papers by this author Published:15 October 1996https://doi.org/10.1098/rsta.1996.0101AbstractThe status quo of the research on Bloch oscillations in semiconductor superlattices is outlined. Bloch oscillations excited by femtosecond laser pulses have been investigated by different optical techniques. They have allowed measurement of the internal electric field changes associated with the charge oscillations, the emitted terahertz electromagnetic radiation and the nonlinear coherent optical response, all directly in the time domain. The main results are summarized and critically reviewed. The potential of Bloch oscillations for practical applications in terahertz radiation sources is assessed.FootnotesThis text was harvested from a scanned image of the original document using optical character recognition (OCR) software. As such, it may contain errors. Please contact the Royal Society if you find an error you would like to see corrected. Mathematical notations produced through Infty OCR. Previous ArticleNext Article VIEW FULL TEXT DOWNLOAD PDF FiguresRelatedReferencesDetailsCited by Islam Q, Meng F, Thomson M and Roskos H (2020) Terahertz photoconductive waveguide emitter with excitation by a tilted optical pulse front, Optics Express, 10.1364/OE.403161, 28:22, (33673), Online publication date: 26-Oct-2020. Gruzdev V and Sergaeva O (2018) Ultrafast modification of band structure of wide-band-gap solids by ultrashort pulses of laser-driven electron oscillations, Physical Review B, 10.1103/PhysRevB.98.115202, 98:11 Vakhnenko O (2016) Coupling-governed metamorphoses of the integrable nonlinear Schrödinger system on a triangular-lattice ribbon, Physics Letters A, 10.1016/j.physleta.2016.04.034, 380:24, (2069-2074), Online publication date: 1-May-2016. Muniz C and Cunha M (2015) Effects of strong electric fields in a polyacetylene chain, Journal of Physics and Chemistry of Solids, 10.1016/j.jpcs.2015.02.009, 82, (17-20), Online publication date: 1-Jul-2015. Sokolov V and Iafrate G (2012) Spontaneous Emission of Bloch Oscillation Radiation in the Terahertz Regime Handbook of Nanoscience, Engineering, and Technology, Third Edition, 10.1201/b11930-9, (67-124), Online publication date: 15-Jun-2012. Belotelov V, Bykov D, Doskolovich L and Zvezdin A (2010) On surface plasmon polariton wavepacket dynamics in metal–dielectric heterostructures, Journal of Physics: Condensed Matter, 10.1088/0953-8984/22/39/395301, 22:39, (395301), Online publication date: 6-Oct-2010. Hummel A, Bauer T, Mohler E and Roskos H (2006) The coherent Hall effect of charge carriers in a superlattice: semiclassical description of the wavepacket dynamics, Journal of Physics: Condensed Matter, 10.1088/0953-8984/18/8/013, 18:8, (2487-2509), Online publication date: 1-Mar-2006. Axt V and Kuhn T (2004) Femtosecond spectroscopy in semiconductors: a key to coherences, correlations and quantum kinetics, Reports on Progress in Physics, 10.1088/0034-4885/67/4/R01, 67:4, (433-512), Online publication date: 1-Apr-2004. Gaidis M, Lee K, Samoska L and Wyss R Frequency-controlled sources of far-infrared radiation for spaceborne applications 2000 IEEE/EIA International Frequency Control Symposium and Exhibition, 10.1109/FREQ.2000.887419, 0-7803-5838-4, (565-577) Kempa K, Bakshi P, Du C, Feng G, Scorupsky A, Strasser G, Rauch C, Unterrainer K and Gornik E (1999) Towards stimulated generation of coherent plasmons in nanostructures, Journal of Applied Physics, 10.1063/1.369736, 85:7, (3708-3712), Online publication date: 1-Apr-1999. Wolter F, Martini R, Tolk S, Haring Bolivar P, Kurz H, Hey R and Grahn H (1999) Influence of carrier–carrier scattering on intraband dephasing, Superlattices and Microstructures, 10.1006/spmi.1999.0763, 26:2, (93-102), Online publication date: 1-Aug-1999. Shah J (1999) Recent Developments Ultrafast Spectroscopy of Semiconductors and Semiconductor Nanostructures, 10.1007/978-3-662-03770-6_9, (325-446), . Luban M and Luscombe J (1998) Dynamical localization of electrons in an aperiodic superlattice, Physical Review B, 10.1103/PhysRevB.57.9043, 57:15, (9043-9049) Chamberlain J, Miles R, Collins C and Steenson D (1997) Introduction to Terahertz Solid-State Devices New Directions in Terahertz Technology, 10.1007/978-94-011-5760-5_1, (3-27), . Cho G, Ziebell A, Dekorsy T, Bakker H, Opitz U, Kohl A and Kurz H (1997) Electroabsorption Dynamics in an InGaAsP/InGaAsP Superlattice Modulator Ultrafast Electronics and Optoelectronics, 10.1364/UEO.1997.UG5, 1-55752-486-6, (UG5) This Issue15 October 1996Volume 354Issue 1717 Article InformationDOI:https://doi.org/10.1098/rsta.1996.0101Published by:Royal SocietyPrint ISSN:1364-503XOnline ISSN:1471-2962History: Published online01/01/1997Published in print15/10/1996 License:Scanned images copyright © 2017, Royal Society Citations and impact

Singularities in the absorption spectrum of guided TM modes in metal–dielectric heterostructures with narrow-gap electronic excitation of a buffer layer

A theoretical investigation is made of the absorption spectrum of guided TM modes in a four-layer planar metal–dielectric waveguide heterostnicture with narrow-gap electronic excitation of a buffer layer in the case when the electronic transition frequency is close to the frequency of a resonance between the guided TM modes in a three-layer dielectric wave-guide and a surface plasmon. It is shown that two types of singularity—dips (antiresonances) and shifted lines—may appear in the absorption spectrum of the guided TM modes of a four-layer heterostnicture. Potential integrated-optics applications of the predicted effect are considered.