Imperial College London

DrRupertOulton

Faculty of Natural SciencesDepartment of Physics

Reader in Physics
 
 
 
//

Contact

 

+44 (0)20 7594 7576r.oulton

 
 
//

Location

 

914Blackett LaboratorySouth Kensington Campus

//

Summary

 

Publications

Publication Type
Year
to

139 results found

Sistani M, Bartmann MG, Gusken NA, Oulton RF, Keshmiri H, Seifner MS, Barth S, Fukata N, Luong MA, den Hertog MI, Lugstein Aet al., 2019, Nanoscale aluminum plasmonic waveguide with monolithically integrated germanium detector, Applied Physics Letters, Vol: 115, Pages: 161107-1-161107-4, ISSN: 0003-6951

Surface plasmon polaritons have rapidly established themselves as a promising concept for molecular sensing, near-field nanoimaging, andtransmission lines for emerging integrated ultracompact photonic circuits. In this letter, we demonstrate a highly compact surface plasmonpolariton detector based on an axial metal-semiconductor-metal nanowire heterostructure device. Here, an in-coupled surface plasmonpolariton propagates along an aluminum nanowire waveguide joined to a high index germanium segment, which effectively acts as a photoconductor at low bias. Based on this system, we experimentally verify surface plasmon propagation along monocrystalline Al nanowires asthin as 40 nm in diameters. Furthermore, the monolithic integration of plasmon generation, guiding, and detection enables us to examine thebending losses of kinked waveguides. These systematic investigations of ultrathin monocrystalline Al nanowires represent a general platformfor the evaluation of nanoscale metal based waveguides for transmission lines of next generation high-speed ultracompact on-chip photoniccircuits.

Journal article

Gennaro SD, Li Y, Maier SA, Oulton RFet al., 2019, Nonlinear Pancharatnam-Berry Phase Metasurfaces beyond the Dipole Approximation, ACS PHOTONICS, Vol: 6, Pages: 2335-2341, ISSN: 2330-4022

Journal article

Grandi S, Nielsen MP, Cambiasso J, Boissier S, Major K, Reardon C, Krauss TF, Oulton R, Hinds E, Clark Aet al., 2019, Hybrid plasmonic waveguide coupling of photons from a single molecule, APL Photonics, Vol: 4, Pages: 086101-1-086101-6, ISSN: 2378-0967

We demonstrate the emission of photons from a single molecule into a hybrid gap plasmon waveguide (HGPW). Crystals of anthracene, doped with dibenzoterrylene (DBT), are grown on top of the waveguides. We investigate a single DBT molecule coupled to the plasmonic region of one of the guides, and determine its in-plane orientation, excited state lifetime and saturation intensity. The molecule emits light into the guide, which is remotely out-coupled by a grating. The second-order autocorrelation and cross-correlation functions show that the emitter is a single molecule and that the light emerging from the grating comes from that molecule. The couplinge fficiency is found to be βWG = 11.6(1:5)%. This type of structure is promising for building new functionality into quantum-photonic circuits, where localised regions of strong emitter-guide coupling can be interconnected by low-loss dielectric guides.

Journal article

Grinblat G, Abdelwahab I, Nielsen MP, Dichtl P, Leng K, Oulton RF, Loh KP, Maier SAet al., 2019, Ultrafast All-Optical Modulation in 2D Hybrid Perovskites, ACS NANO, Vol: 13, Pages: 9504-9510, ISSN: 1936-0851

Journal article

Doiron B, Li Y, Mihai A, Bower R, Alford NM, Petrov PK, Maier SA, Oulton RFet al., 2019, Plasmon-enhanced electron harvesting in robust titanium nitride nanostructures, The Journal of Physical Chemistry Part C: Nanomaterials and Interfaces, Vol: 123, Pages: 18521-18527, ISSN: 1932-7447

Titanium nitride (TiN) continues to prove itself as an inexpensive, robust, and efficient alternative to gold in plasmonic applications. Notably, TiN has improved hot electron-harvesting and photocatalytic abilities compared to gold systems, which we recently attributed to the role of oxygen in TiN and its native semiconducting TiO2–x surface layer. Here, we explore the role of localized surface plasmon resonances (LSPRs) on electron harvesting across the TiN/TiO2–x interface and probe the resilience of TiN nanostructures under high-power laser illumination. To investigate this, we fabricate TiN strips, in which the lateral confinement allows for the polarization-selective excitation of the LSPR. Using ultrafast pump–probe spectroscopy, optical characterization, and Raman vibrational spectroscopy, we relate the differences and changes observed in the electron behavior to specific material properties. We observe plasmon-enhanced electron harvesting beyond what is expected resulting from the enhanced absorption of the plasmonic mode. We accredit this to the surface oxide damping the plasmon resonance, providing additional nonradiative loss channels. Subsequently, we show that low-power annealing of the surface oxide layer reduces the trap density at the interface and increases the initial harvested electron concentration. The unique properties of TiN make it important in the future development of plasmonic electron-harvesting applications.

Journal article

Abdelwahab I, Dichtl P, Grinblat G, Leng K, Chi X, Park I-H, Nielsen MP, Oulton RF, Loh KP, Maier SAet al., 2019, Giant and Tunable Optical Nonlinearity in Single-Crystalline 2D Perovskites due to Excitonic and Plasma Effects, ADVANCED MATERIALS, Vol: 31, ISSN: 0935-9648

Journal article

Grinblat G, Nielsen M, Dichtl P, Li Y, Oulton R, Maier Set al., 2019, Ultrafast sub-30 FS all-optical switching based on gallium phosphide, Science Advances, Vol: 5, ISSN: 2375-2548

Gallium Phosphide (GaP) is one of the few available materials with strong optical nonlinearity and negligible losses in the visible ( >450 )and near-infrared regime. In this work, we demonstrate that a GaP film can generate sub-30 fs (full width at half maximum) transmission modulation of up to ⁓70% in the 600-1000 nm wavelength range. Nonlinear simulations using parameters measured by the Z-scan approach indicate that the transmission modulation arises from the optical Kerr effect and two-photon absorption. Due to the absence of linear absorption, no slower free-carrier contribution is detected. These findings place GaP as a promising ultrafast material for all-optical switching at modulation speeds of up to 20 THz.

Journal article

Grandi S, Nielsen MP, Cambiasso J, Boissier S, Major KD, Reardon C, Krauss TF, Oulton RF, Hinds EA, Clark ASet al., 2019, Hybrid plasmonic waveguide coupling of photons from a single molecule

We demonstrate the emission of photons from a single molecule into a hybridgap plasmon waveguide (HGPW). Crystals of anthracene, doped withdibenzoterrylene (DBT), are grown on top of the waveguides. We investigate asingle DBT molecule coupled to the plasmonic region of one of the guides, anddetermine its in-plane orientation, excited state lifetime and saturationintensity. The molecule emits light into the guide, which is remotelyout-coupled by a grating. The second-order auto-correlation andcross-correlation functions show that the emitter is a single molecule and thatthe light emerging from the grating comes from that molecule. The couplingefficiency is found to be $\beta_{WG}=11.6(1.5)\%$. This type of structure ispromising for building new functionality into quantum-photonic circuits, wherelocalised regions of strong emitter-guide coupling can be interconnected bylow-loss dielectric guides.

Working paper

Gusken NA, Nielsen MP, Nguyen NB, Shi X, Dichtl P, Maier SA, Oulton RFet al., 2019, Efficient four wave mixing and low-loss in-coupling in hybrid gap plasmonic waveguides

© 2019 The Author(s) 2019 OSA. We show efficient four-wave-mixing over μm length-scales with a signal-to-idler conversion efficiency of 1% enabled by strong nonlinearities and highly confined fields. Furthermore, we demonstrate low-loss in-coupling into nanometer gaps with an efficiency of 80%.

Conference paper

Aizpurua J, Ashfold M, Baletto F, Baumberg J, Christopher P, Cortés E, de Nijs B, Diaz Fernandez Y, Gargiulo J, Gawinkowski S, Halas N, Hamans R, Jankiewicz B, Khurgin J, Kumar PV, Liu J, Maier S, Maurer RJ, Mount A, Mueller NS, Oulton R, Parente M, Park JY, Polanyi J, Quiroz J, Rejman S, Schlücker S, Schultz Z, Sivan Y, Tagliabue G, Thangamuthu M, Torrente-Murciano L, Xiao X, Zayats A, Zhan Cet al., 2019, Dynamics of hot electron generation in metallic nanostructures: general discussion., Faraday Discuss, Vol: 214, Pages: 123-146

Journal article

Shautsova V, Gusken NA, Sidiropoulos T, Xiao X, Black NCG, Gilbertson AM, Giannini V, Maier SA, Cohen LF, Oulton RFet al., 2019, Plasmonic photo-thermo-electric effect in graphene

© 2019 The Author(s) 2019 OSA. We present a novel photo-thermo-electric effect in graphene photo-detectors established by hot electrons concentration gradients at plasmonic contacts. Our description is crucial for an in depth understanding of graphene-based photo detection devices.

Conference paper

Gusken NA, Lauri A, Li Y, Matsui T, Doiron B, Bower R, Regoutz A, Mihai A, Petrov PK, Oulton RF, Cohen LF, Maier SAet al., 2019, TiO2-x-enhanced IR hot carrier based photodetection in metal thin film-si junctions, ACS Photonics, Vol: 6, Pages: 953-960, ISSN: 2330-4022

We investigate titanium nitride (TiN) thin film coatings on silicon for CMOS-compatible sub-bandgap charge separation upon incident illumination, which is a key feature in the vast field of on-chip photodetection and related integrated photonic devices. Titanium nitride of tunable oxidation distributions serves as an adjustable broadband light absorber with high mechanical robustness and strong chemical resistivity. Backside-illuminated TiN on p-type Si (pSi) constitutes a self-powered and refractory alternative for photodetection, providing a photoresponsivity of about ∼1 mA/W at 1250 nm and zero bias while outperforming conventional metal coatings such as gold (Au). Our study discloses that the enhanced photoresponse of TiN/pSi in the near-infrared spectral range is directly linked to trap states in an ultrathin TiO2–x interfacial interlayer that forms between TiN and Si. We show that a pSi substrate in conjunction with a few nanometer thick amorphous TiO2–x film can serve as a platform for photocurrent enhancement of various other metals such as Au and Ti. Moreover, the photoresponse of Au on a TiO2–x/pSi platform can be increased to about 4 mA/W under 0.45 V reverse bias at 1250 nm, allowing for controlled photoswitching. A clear deviation from the typically assumed Fowler-like response is observed, and an alternative mechanism is proposed to account for the metal/semiconductor TiO2–x interlayer, capable of facilitating hole transport.

Journal article

Doiron B, Mota M, Wells MP, Bower R, Mihai A, Li Y, Cohen LF, Alford NM, Petrov PK, Oulton RF, Maier SAet al., 2019, Quantifying figures of merit for localized surface plasmon resonance applications: a materials survey, ACS Photonics, Vol: 6, Pages: 240-259, ISSN: 2330-4022

Using localized surface plasmon resonances (LSPR) to focus electromagnetic radiation to the nanoscale shows the promise of unprecedented capabilities in optoelectronic devices, medical treatments and nanoscale chemistry, due to a strong enhancement of light-matter interactions. As we continue to explore novel applications, we require a systematic quantitative method to compare suitability across different geometries and a growing library of materials. In this work, we propose application-specific figures of merit constructed from fundamental electronic and optical properties of each material. We compare 17 materials from four material classes (noble metals, refractory metals, transition metal nitrides, and conductive oxides) considering eight topical LSPR applications. Our figures of merit go beyond purely electromagnetic effects and account for the materials’ thermal properties, interactions with adjacent materials, and realistic illumination conditions. For each application we compare, for simplicity, an optimized spherical antenna geometry and benchmark our proposed choice against the state-of-the-art from the literature. Our propositions suggest the most suitable plasmonic materials for key technology applications and can act as a starting point for those working directly on the design, fabrication, and testing of such devices.

Journal article

Shautsova V, Gusken NA, Sidiropoulos T, Xiao X, Black NCG, Gilbertson AM, Giannini V, Maier SA, Cohen LF, Oulton RFet al., 2019, Plasmonic photo-thermo-electric effect in graphene, Conference on Lasers and Electro-Optics (CLEO), Publisher: IEEE, ISSN: 2160-9020

Conference paper

Ma R-M, Oulton RF, 2019, Applications of nanolasers, NATURE NANOTECHNOLOGY, Vol: 14, Pages: 12-22, ISSN: 1748-3387

Journal article

Gusken NA, Nielsen MP, Nguyen NB, Shi X, Dichtl P, Maier SA, Oulton RFet al., 2019, Efficient four wave mixing and low-loss in-coupling in hybrid gap plasmonic waveguides, Conference on Lasers and Electro-Optics (CLEO), Publisher: IEEE, ISSN: 2160-9020

Conference paper

Grinblat G, Berte R, Nielsen MP, Li Y, Oulton RF, Maier SAet al., 2018, Sub-20 fs all-optical switching in a single Au-Clad Si nanodisk, Nano Letters, Vol: 18, Pages: 7896-7900, ISSN: 1530-6984

Dielectric nanoantennas have recently emerged as promising elements for nonlinear and ultrafast nanophotonics due to their ability to concentrate light on the nanometer scale with low losses, while exhibiting large nonlinear susceptibilities. In this work, we demonstrate that single Si nanodisks covered with a thin 30 nm thick layer of Au can generate positive and negative sub-20 fs reflectivity modulations of ∼0.3% in the vicinity of the first-order anapole mode, when excited around the second-order anapole mode. The experimental results, characterized in the visible to near-infrared spectral range, suggest that the nonlinear optical Kerr effect is the responsible mechanism for the observed all-optical switching phenomena. These findings represent an important step toward nanoscale ultrafast all-optical signal processing.

Journal article

Shautsova V, Sidiropoulos T, Xiao X, Gusken N, Black N, Gilbertson A, Maier S, Cohen L, Oulton Ret al., 2018, Plasmon induced thermoelectric effect in graphene, Nature Communications, Vol: 9, ISSN: 2041-1723

Graphene has emerged as a promising material for optoelectronics due to its potential for ultrafast and broad-band photodetection. The photoresponse of graphene junctions is characterized by two competing photocurrent generation mechanisms: a conventional photovoltaic effect and a more dominant hot-carrier-assisted photothermoelectric (PTE) effect. The PTE effect is understood to rely on variations in the Seebeck coefficient through the graphene doping profile. A second PTE effect can occur across a homogeneous graphene channel in the presence of an electronic temperature gradient. Here, we study the latter effect facilitated by strongly localised plasmonic heating of graphene carriers in the presence of nanostructured electrical contacts resulting in electronic temperatures of the order of 2000 K. At certain conditions, the plasmon-induced PTE photocurrent contribution can be isolated. In this regime, the device effectively operates as a sensitive electronic thermometer and as such represents an enabling technology for development of hot carrier based plasmonic devices.

Journal article

Gusken N, Nielsen M, Nguyen N, Maier S, Oulton Ret al., 2018, Nanofocusing in SOI-based hybrid plasmonic metal slot waveguides, Optics Express, Vol: 26, Pages: 30634-30643, ISSN: 1094-4087

Abstract: Through a process of efficient dielectric to metallic waveguide mode conversion, we calculate a >400-fold field intensity enhancement in a silicon photonics compatible nanofocusing device. A metallic slot waveguide sits on top of the silicon slab waveguide with nanofocusing being achieved by tapering the slot width gradually. We evaluate the conversion between the numerous photonic modes of the planar silicon waveguide slab and the most confined plasmonic mode of a 20 x 50 nm2 slot in the metallic film. With an efficiency of ~80%, this system enables remarkably effective nanofocusing, although the small amount of inter-mode coupling shows that this structure is not quite adiabatic. In order to couple photonic and plasmonic modes efficiently, in-plane focusing is required, simulated here by curved input grating couplers. The nanofocusing device shows how to efficiently bridge the photonic micro-regime and the plasmonic nano-regime whilst maintaining compatibility with the silicon photonics platform.

Journal article

Kumar R, Verzhbitskiy I, Giustiniano F, Sidiropoulos TPH, Oulton RF, Eda Get al., 2018, Interlayer screening effects in WS2/WSe2 van der Waals hetero-bilayer, 2D MATERIALS, Vol: 5, ISSN: 2053-1583

Journal article

Gennaro SD, Li Y, Maier SA, Oulton RFet al., 2018, Double blind ultrafast pulse characterization by mixed frequency generation in a gold antenna, ACS Photonics, Vol: 5, Pages: 3166-3171, ISSN: 2330-4022

Ultrafast pulse characterization requires the analysis of correlation functions generated by frequency mixing of optical pulses in a nonlinear medium. In this work, we use a gold optical nanoantenna to generate simultaneously Four Wave Mixing and Sum Frequency Generation across the tuning range of a Ti: Sapphire and Optical Parametric Oscillator (OPO) system. Since metal nanoparticles create remarkably strong nonlinear responses for their size without the need for phase matching, this allows us to simultaneously characterize the unknown OPO pulse and its pump pulse using a single spectrogram. The nonlinear mixing is efficient enough to retrieve pulses with energies in the picojoule range.

Journal article

Wells M, Bower R, Kilmurray B, Zou B, Mihai AP, GOBALAKRICHENANE G, Alford NM, Oulton RFM, Cohen L, Maier SA, ZAYATS A, Petrov PKet al., 2018, Temperature stability of thin film refractory plasmonic materials, Optics Express, Vol: 12, Pages: 15726-15744, ISSN: 1094-4087

Materials such as W, TiN, and SrRuO3 (SRO) have been suggested as promising alternatives to Au and Ag in plasmonic applications owing to their stability at high operational temperatures. However, investigation of the reproducibility of the optical properties after thermal cycling between room and elevated temperatures is so far lacking. Here, thin films of W, Mo, Ti, TiN, TiON, Ag, Au, SrRuO3 and SrNbO3 are investigated to assess their viability for robust refractory plasmonic applications. These results are further compared to the performance of SrMoO3 reported in literature. Films ranging in thickness from 50 to 105 nm are deposited on MgO, SrTiO3 and Si substrates by e-beam evaporation, RF magnetron sputtering and pulsed laser deposition, prior to characterisation by means of AFM, XRD, spectroscopic ellipsometry, and DC resistivity. Measurements are conducted before and after annealing in air at temperatures ranging from 300 to 1000° C for one hour, to establish the maximum cycling temperature and potential longevity at elevated temperatures for each material. It is found that SrRuO3 retains metallic behaviour after annealing at 800° C, while SrNbO3 undergoes a phase transition resulting in a loss of metallic behaviour after annealing at 400° C. Importantly, the optical properties of TiN and TiON are degraded as a result of oxidation and show a loss of metallic behaviour after annealing at 500° C, while the same is not observed in Au until annealing at 600° C. Nevertheless, both TiN and TiON may be better suited than Au or SRO for high temperature applications operating under vacuum conditions.

Journal article

Matsui T, Li Y, Hsu M-HM, Merckling C, Oulton RF, Cohen LF, Maier SAet al., 2018, Highly Stable Plasmon Induced Hot Hole Transfer into Silicon via a SrTiO3 Passivation Interface, ADVANCED FUNCTIONAL MATERIALS, Vol: 28, ISSN: 1616-301X

Extracting plasmon‐induced hot carriers over a metal–semiconductor Schottky barrier enables photodetection below the semiconductor bandgap energy. However, interfacial carrier recombination hinders the efficiency and stability of this process, severely limiting its implementation in telecommunication. This study proposes and demonstrates the use of epitaxially grown lattice‐matched SrTiO3 for interfacial passivation of silicon‐based plasmonic Schottky devices. The devices are activated by an electrical soft‐breakdown of the interfacial SrTiO3 layer, resulting in reproducible rectified Schottky characteristics. The transition to a low resistance state of the SrTiO3 layer boosts the extraction efficiency of hot holes upon resonant plasmonic excitation, giving rise to a two orders of magnitude higher photocurrent compared to devices with a native oxide layer. Photoresponse, tunability, and barrier height studies under reverse biases as high as 100 V present superior stability with the incorporation of the SrTiO3 layer. The investigation paves the way toward plasmon‐induced photodetection for practical applications including those under challenging operating conditions.

Journal article

Mignuzzi S, Mota M, Coenen T, Li Y, Mihai A, Petrov PK, Oulton RF, Maier SA, Sapienza Ret al., 2018, Energy-momentum cathodoluminescence spectroscopy of dielectric nanostructures, ACS Photonics, Vol: 5, Pages: 1381-1387, ISSN: 2330-4022

Precise knowledge of the local density of optical states (LDOS) is fundamental to understanding nanophotonic systems and devices. Complete LDOS mapping requires resolution in energy, momentum, and space, and hence a versatile measurement approach capable of providing simultaneous access to the LDOS components is highly desirable. Here, we explore a modality of cathodoluminescence spectroscopy able to resolve, in single acquisitions, the dispersion in energy and momentum of the radiative LDOS. We perform measurements on a titanium nitride diffraction grating, bulk molybdenum disulfide, and silicon to demonstrate that the technique can probe and disentangle the dispersion of coherent and incoherent cathodoluminescence signals. The approach presented raises cathodoluminescence spectroscopy to a versatile tool for subwavelength design and optimization of nanophotonic devices in the reciprocal space.

Journal article

München, Matsui T, Li Y, Oulton RF, Cohen LF, Maier SAet al., 2018, Plasmonic hot carrier detection via SrTiO<inf>3</inf> interfacial layer

© 2018 OSA - The Optical Society. All rights reserved. Energetic hot carrier injection from metal plasmonic structure to adjacent semiconductor lies at the center of the application of non-radiative decays, photochemical reactions and energy harvesting. Plasmonic hot-electron devices, till now, have been highly focused on a Schottky barrier structures to separate the energetic carriers before the thermalization. For instance, much efforts were putted in exploring high absorption structure with enough thin metal; enough thin compared to mean free path. However, interfacial engineering of the device; exploring a new device structure, have not been fully investigated.

Conference paper

Nielsen MP, Nicholas, Gusken, Shi X, Dichtl P, Maier SA, Oulton RFet al., 2018, Giant nonlinear response at a plasmonic nanofocus drives efficient four wave mixing over micron length scales

© 2018 The Author(s). We demonstrate four wave mixing in an integrated plasmonic gap waveguide on silicon that strongly confines light within a nonlinear organic polymer. We report >1% signal to idler conversion efficiency over micron-scale interaction lengths.

Conference paper

Nguyen NB, Nielsen MP, Lafone L, Clarke E, Fry P, Oulton RFet al., 2017, Hybrid gap plasmon GaAs nanolasers, APPLIED PHYSICS LETTERS, Vol: 111, ISSN: 0003-6951

Journal article

Nielsen MP, Shi X, Dichtl P, Maier SA, Oulton RFet al., 2017, Giant nonlinear response at a plasmonic nanofocus drives efficient four-wave mixing, Science, Vol: 358, Pages: 1179-1181, ISSN: 0036-8075

Efficient optical frequency mixing typically must accumulate over large interaction lengths because nonlinear responses in natural materials are inherently weak. This limits the efficiency of mixing processes owing to the requirement of phase matching. Here, we report efficient four-wave mixing (FWM) over micrometer-scale interaction lengths at telecommunications wavelengths on silicon. We used an integrated plasmonic gap waveguide that strongly confines light within a nonlinear organic polymer. The gap waveguide intensifies light by nanofocusing it to a mode cross-section of a few tens of nanometers, thus generating a nonlinear response so strong that efficient FWM accumulates over wavelength-scale distances. This technique opens up nonlinear optics to a regime of relaxed phase matching, with the possibility of compact, broadband, and efficient frequency mixing integrated with silicon photonics.

Journal article

Wang S, Wang X-Y, Li B, Chen H-Z, Wang Y-L, Dai L, Oulton RF, Ma R-Met al., 2017, Unusual scaling laws for plasmonic nanolasers beyond the diffraction limit., Nature Communications, Vol: 8, ISSN: 2041-1723

Plasmonic nanolasers are a new class of amplifiers that generate coherent light well below the diffraction barrier bringing fundamentally new capabilities to biochemical sensing, super-resolution imaging, and on-chip optical communication. However, a debate about whether metals can enhance the performance of lasers has persisted due to the unavoidable fact that metallic absorption intrinsically scales with field confinement. Here, we report plasmonic nanolasers with extremely low thresholds on the order of 10 kW cm-2 at room temperature, which are comparable to those found in modern laser diodes. More importantly, we find unusual scaling laws allowing plasmonic lasers to be more compact and faster with lower threshold and power consumption than photonic lasers when the cavity size approaches or surpasses the diffraction limit. This clarifies the long-standing debate over the viability of metal confinement and feedback strategies in laser technology and identifies situations where plasmonic lasers can have clear practical advantage.

Journal article

Wells MP, Zou B, Doiron BG, Kilmurray R, Mihai AP, Oulton RF, Gubeljak P, Ormandy K, Mallia G, Harrison N, Cohen LF, Maier S, Petrov PKet al., 2017, Tunable, Low Optical Loss Strontium Molybdate Thin Films for Plasmonic Applications, Advanced Optical Materials, Vol: 5, ISSN: 2195-1071

Strontium molybdate (SrMoO3) thin films are grown epitaxially on strontium titanate (SrTiO3), magnesium oxide (MgO), and lanthanum aluminate (LaAlO3) substrates by pulsed laser deposition and possess electrical resistivity as low as 100 µΩ cm at room temperature. SrMoO3 is shown to have optical losses, characterized by the product of the Drude broadening, ΓD, and the square of the plasma frequency, ωpu2, significantly lower than TiN, though generally higher than Au. Also, it is demonstrated that there is a zero-crossover wavelength of the real part of the dielectric permittivity, which is between 600 and 950 nm (2.05 and 1.31 eV), as measured by spectroscopic ellipsometry. Moreover, the epsilon near zero (ENZ) wavelength can be controlled by engineering the residual strain in the films, which arises from a strain dependence of the charge carrier concentration, as confirmed by density of states calculations. The relatively broad tunability of ENZ behavior observed in SrMoO3 demonstrates its potential suitability for transformation optics along with plasmonic applications in the visible to near infrared spectral range.

Journal article

This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.

Request URL: http://wlsprd.imperial.ac.uk:80/respub/WEB-INF/jsp/search-html.jsp Request URI: /respub/WEB-INF/jsp/search-html.jsp Query String: respub-action=search.html&id=00168304&limit=30&person=true