Publications
187 results found
Nielsen MP, Lafone L, Rakovich A, et al., 2016, Adiabatic nanofocusing in hybrid gap plasmon waveguides on the silicon-on-insulator platform, Nano Letters, Vol: 16, Pages: 1410-1414, ISSN: 1530-6992
We present an experimental demonstration of a new class of hybrid gap plasmon waveguides on the silicon-on-insulator (SOI) platform. Created by the hybridization of the plasmonic mode of a gap in a thin metal sheet and the transverse-electric (TE) photonic mode of an SOI slab, this waveguide is designed for efficient adiabatic nanofocusing simply by varying the gap width. For gap widths greater than 100 nm, the mode is primarily photonic in character and propagation lengths can be many tens of micrometers. For gap widths below 100 nm, the mode becomes plasmonic in character with field confinement predominantly within the gap region and with propagation lengths of a few microns. We estimate the electric field intensity enhancement in hybrid gap plasmon waveguide tapers at 1550 nm by three-photon absorption of selectively deposited CdSe/ZnS quantum dots within the gap. Here, we show electric field intensity enhancements of up to 167 ± 26 for a 24 nm gap, proving the viability of low loss adiabatic nanofocusing on a commercially relevant photonics platform.
Wilkinson JT, Whitehouse CB, Oulton RF, et al., 2016, An undergraduate experiment demonstrating the physics of metamaterials with acoustic waves and soda cans, American Journal of Physics, Vol: 84, Pages: 14-20, ISSN: 0002-9505
We describe a novel undergraduate research project that highlights the physics of metamaterials withacoustic waves and soda cans. We confirm the Helmholtz resonance nature of a single can bymeasuring its amplitude and phase response to a sound wave. Arranging multiple cans in arrayssmaller than the wavelength, we then design an antenna that redirects sound into a preferred direction.The antenna can be thought of as a new resonator, composed of artificially engineered meta-atoms,similar to a metamaterial. These experiments are illustrative, tactile, and open ended so as to enablestudents to explore the physics of matter/wave interaction
Sidiropoulos TPH, Röder R, Geburt S, et al., 2016, Ultrafast ZnO nanowire lasers: nanoplasmonic acceleration of gain dynamics at the surface plasmon polariton frequency
We report optically pumped hybrid photonic - plasmonic ZnO nanowire lasers operating near the surface plasmon frequency. Here, we use the non-linearity of the laser process itself to reveal the internal ~1 ps dynamics of these plasmonic lasers.
Lafone L, Nguyen N, Nielsen MP, et al., 2016, Printed Plasmonic GaAs Nanolasers
We present optically-pumped plasmonic GaAs nanolasers operating at room temperature. Built on suspended GaAs membranes, the etchless fabrication involves only a printed metal film, which defines the plasmonic cavity and confines the optical mode.
Nielsen MP, Lafone L, Rakovich A, et al., 2016, Hybrid gap plasmon waveguides on the silicon-on-insulator platform for adiabatic nanofocusing
We present a new class of silicon hybrid gap plasmon waveguides designed for adiabatic nanofocusing. Using a 3-photon absorption process in quantum dots, we show a 167±26 intensity enhancement for a 24nm wide waveguide.
Nielsen MP, Lafone L, Nguyen N, et al., 2016, Generating Intense Optical Fields with Hybrid-gap Plasmon Lasers, Progress in Electromagnetic Research Symposium (PIERS), Publisher: IEEE, Pages: 31-31
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- Citations: 4
Lafone L, Ngoc N, Nielsen MP, et al., 2016, Printed Plasmonic GaAs Nanolasers, Conference on Lasers and Electro-Optics (CLEO), Publisher: IEEE, ISSN: 2160-9020
Sidiropoulos TPH, Roeder R, Geburt S, et al., 2016, Ultrafast ZnO nanowire lasers: nanoplasmonic acceleration of gain dynamics at the surface plasmon polariton frequency, Conference on Lasers and Electro-Optics (CLEO), Publisher: IEEE, ISSN: 2160-9020
Nielsen MP, Lafone L, Rakovich A, et al., 2016, Hybrid gap plasmon waveguides on the silicon-on-insulator platform for adiabatic nanofocusing, Conference on Lasers and Electro-Optics (CLEO), Publisher: IEEE, ISSN: 2160-9020
Rahmani M, Gennaro SD, Giannini V, et al., 2016, Linearly Polarized Dipolar Second Harmonic Generation from Gold Nano-antennas by Controlling Their Radiation Phase, Progress in Electromagnetic Research Symposium (PIERS), Publisher: IEEE, Pages: 2292-2292
Duffin TJ, Nielsen MP, Diaz F, et al., 2015, Degenerate four-wave mixing in silicon hybrid plasmonic waveguides, Optics Letters, Vol: 41, Pages: 155-158, ISSN: 1539-4794
Silicon-based plasmonic waveguides show high confinementwell beyond the diffraction limit. Various deviceshave been demonstrated to outperform their dielectriccounterparts at micrometre scales, such as linearmodulators, capable of generating high field confinementand improving device efficiency by increasingaccess to nonlinear processes, limited by ohmiclosses. By using hybridised plasmonic waveguide architecturesand nonlinear materials, silicon-based plasmonicwaveguides can generate strong nonlinear effectsover just a few wavelengths. We have theoreticallyinvestigated the nonlinear optical performance of twohybrid plasmonic waveguides (HPWG) with three differentnonlinear materials. Based on this analysis, thehybrid gap plasmon waveguide (HGPW), combinedwith the DDMEBT nonlinear polymer, shows a fourwavemixing (FWM) conversion efficiency of 16.4dBover a 1mm propagation length, demonstrating that plasmonicwaveguides can be competitive with standardsilicon photonics structures over distances three ordersof magnitude shorter.
Wood JJ, Lafone L, Hamm JM, et al., 2015, Plasmonic CROWs for Tunable Dispersion and High Quality Cavity Modes, Scientific Reports, Vol: 5, ISSN: 2045-2322
Coupled resonator optical waveguides (CROWs) have the potential to revolutionise integrated optics, to slow-light and enhance linear and non-linear optical phenomena. Here we exploit the broad resonances and subwavelength nature of localized surface plasmons in a compact CROW design where plasmonic nanoparticles are side coupled to a dielectric waveguide. The plasmonic CROW features a low loss central mode with a highly tunable dispersion, that avoids coupling to the plasmonic nanoparticles close to the band-edge. We show that this low loss character is preserved in finite plasmonic CROWs giving rise to Fabry-Perot type resonances that have high quality factors of many thousands, limited only by the CROW length. Furthermore we demonstrate that the proposed CROW design is surprisingly robust to disorder. By varying the geometric parameters one can not only reduce the losses into dissipative or radiative channels but also control the outcoupling of energy to the waveguide. The ability to minimise loss in plasmonic CROWs while maintaining dispersion provides an effective cavity design for chip-integrated laser devices and applications in linear and non-linear nano-photonics.
Gennaro S, Oulton R, Wilkinson J, et al., 2015, An undergraduate experiment demonstrating the physics of metamaterials with acoustic waves and soda cans, American Journal of Physics, ISSN: 0002-9505
Caldarola M, Albella P, Cortés E, et al., 2015, Non-plasmonic nanoantennas for surface enhanced spectroscopies with ultra-low heat conversion, Nature Communications, Vol: 6, ISSN: 2041-1723
Nanoplasmonics has recently revolutionized our ability to control light on the nanoscale. Using metallic nanostructures with tailored shapes, it is possible to efficiently focus light into nanoscale field 'hot spots'. High field enhancement factors have been achieved in such optical nanoantennas, enabling transformative science in the areas of single molecule interactions, highly enhanced nonlinearities and nanoscale waveguiding. Unfortunately, these large enhancements come at the price of high optical losses due to absorption in the metal, severely limiting real-world applications. Via the realization of a novel nanophotonic platform based on dielectric nanostructures to form efficient nanoantennas with ultra-low light-into-heat conversion, here we demonstrate an approach that overcomes these limitations. We show that dimer-like silicon-based single nanoantennas produce both high surface enhanced fluorescence and surface enhanced Raman scattering, while at the same time generating a negligible temperature increase in their hot spots and surrounding environments.
Liu W, Oulton RF, Kivshar YS, 2015, Geometric interpretations for resonances of plasmonic nanoparticles, Scientific Reports, Vol: 5, ISSN: 2045-2322
The field of plasmonics can be roughly categorized into two branches: surface plasmon polaritons (SPPs) propagating in waveguides and localized surface plasmons (LSPs) supported by scattering particles. Investigations along these two directions usually employ different approaches, resulting in more or less a dogma that the two branches progress almost independently of each other, with few interactions. Here in this work we interpret LSPs from a Bohr model based geometric perspective relying on SPPs, thus establishing a connection between these two sub-fields. Besides the clear explanations of conventional scattering features of plasmonic nanoparticles, based on this geometric model we further demonstrate other anomalous scattering features (higher order modes supported at lower frequencies, and blueshift of the resonance with increasing particle sizes) and multiple electric resonances of the same order supported at different frequencies, which have been revealed to originate from backward SPP modes and multiple dispersion bands supported in the corresponding plasmonic waveguides, respectively. Inspired by this geometric model, it is also shown that, through solely geometric tuning, the absorption of each LSP resonance can be maximized to reach the single channel absorption limit, provided that the scattering and absorption rates are tuned to be equal.
Roeder R, Sidiropoulos TPH, Tessarek C, et al., 2015, Ultrafast Dynamics of Lasing Semiconductor Nanowires, Nano Letters, Vol: 15, Pages: 4637-4643, ISSN: 1530-6992
Semiconductor nanowire lasers operate at ultrafast timescales; here we report their temporal dynamics, including laser onset time and pulse width, using a double-pump approach. Wide bandgap gallium nitride (GaN), zinc oxide (ZnO), and cadmium sulfide (CdS) nanowires reveal laser onset times of a few picoseconds, driven by carrier thermalization within the optically excited semiconductor. Strong carrier–phonon coupling in ZnO leads to the fastest laser onset time of ∼1 ps in comparison to CdS and GaN exhibiting values of ∼2.5 and ∼3.5 ps, respectively. These values are constant between nanowires of different sizes implying independence from any optical influences. However, we demonstrate that the lasing onset times vary with excitation wavelength relative to the semiconductor band gap. Meanwhile, the laser pulse widths are dependent on the optical system. While the fastest ultrashort pulses are attained using the thinnest possible nanowires, a sudden change in pulse width from ∼5 to ∼15 ps occurs at a critical nanowire diameter. We attribute this to the transition from single to multimode waveguiding, as it is accompanied by a change in laser polarization.
Gilbertson AM, Francescato Y, Roschuk T, et al., 2015, Plasmon-Induced Optical Anisotropy in Hybrid Graphene-Metal Nanoparticle Systems, NANO LETTERS, Vol: 15, Pages: 3458-3464, ISSN: 1530-6984
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- Citations: 43
Gennaro SD, Sonnefraud Y, Verellen N, et al., 2015, Spectral interferometric microscopy reveals absorption by individual optical nano-antennas from extinction phase, 9th International Congress on Advanced Electromagnetic Materials in Microwaves and Optics (METAMATERIALS), Publisher: IEEE, Pages: 403-405
Gennaro SD, Roschuk TR, Maier SA, et al., 2015, Measuring chromatic aberration in imaging systems using plasmonic nano-particles, 9th International Congress on Advanced Electromagnetic Materials in Microwaves and Optics (METAMATERIALS), Publisher: IEEE, Pages: 406-408
Lafone L, Ngoc N, Clarke E, et al., 2015, III-V GaAs based plasm onic lasers, Conference on Active Photonic Materials VII, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
Sidiropoulos TPH, Roder R, Geburt S, et al., 2015, Ultrafast plasmonic nanowire lasers near the surface plasmon frequency, Conference on Active Photonic Materials VII, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
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- Citations: 1
Sidiropoulos TPH, Roeder R, Geburt S, et al., 2014, Ultrafast plasmonic nanowire lasers near the surface plasmon frequency, Nature Physics, Vol: 10, Pages: 870-876, ISSN: 1745-2473
Light–matter interactions are inherently slow as the wavelengths of optical and electronic states differ greatly. Surface plasmon polaritons — electromagnetic excitations at metal–dielectric interfaces — have generated significant interest because their spatial scale is decoupled from the vacuum wavelength, promising accelerated light–matter interactions. Although recent reports suggest the possibility of accelerated dynamics in surface plasmon lasers, this remains to be verified. Here, we report the observation of pulses shorter than 800 fs from hybrid plasmonic zinc oxide (ZnO) nanowire lasers. Operating at room temperature, ZnO excitons lie near the surface plasmon frequency in such silver-based plasmonic lasers, leading to accelerated spontaneous recombination, gain switching and gain recovery compared with conventional ZnO nanowire lasers. Surprisingly, the laser dynamics can be as fast as gain thermalization in ZnO, which precludes lasing in the thinnest nanowires (diameter less than 120 nm). The capability to combine surface plasmon localization with ultrafast amplification provides the means for generating extremely intense optical fields, with applications in sensing, nonlinear optical switching, as well as in the physics of strong-field phenomena.
Sidiropoulos TPH, Nielsen MP, Roschuk TR, et al., 2014, Compact Optical Antenna Coupler for Silicon Photonics Characterized by Third-Harmonic Generation, ACS PHOTONICS, Vol: 1, Pages: 912-916, ISSN: 2330-4022
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- Citations: 20
Lafone L, Sidiropoulos TPH, Oulton RF, 2014, Silicon-based metal-loaded plasmonic waveguides for low-loss nanofocusing, OPTICS LETTERS, Vol: 39, Pages: 4356-4359, ISSN: 0146-9592
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- Citations: 31
Lafone L, Sidiropoulos TPH, Hamm JM, et al., 2014, Feasibility of GaAs-based metal strip surface plasmon nano-lasers, IET OPTOELECTRONICS, Vol: 8, Pages: 122-128, ISSN: 1751-8768
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- Citations: 5
Gennaro SD, Sonnefraud Y, Verellen N, et al., 2014, Spectral interferometric microscopy reveals absorption by individual optical nanoantennas from extinction phase, NATURE COMMUNICATIONS, Vol: 5, ISSN: 2041-1723
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- Citations: 25
Sidiropoulos TPH, Geburt S, Röder R, et al., 2014, Ultrafast ZnO nanowire lasers: Nanoplasmonic acceleration of gain dynamics at the surface plasmon polariton frequency
We report optically pumped hybrid photonic - plasmonic ZnO nanowire lasers operating near the surface plasmon frequency. Here, we use the non-linearity of the laser process itself to reveal the internal ∼1 ps dynamics of these plasmonic lasers.
Sidiropoulos TPH, Geburt S, Roeder R, et al., 2014, Ultrafast ZnO nanowire lasers: nanoplasmonic acceleration of gain dynamics at the surface plasmon polariton frequency, Conference on Lasers and Electro-Optics (CLEO), Publisher: IEEE, ISSN: 2160-9020
Gennaro SD, Sonnefraud Y, Verellen N, et al., 2014, Spectral interferometric microscopy reveals absorption by individual optical nano-antennas from extinction phase, Conference on Lasers and Electro-Optics (CLEO), Publisher: IEEE, ISSN: 2160-9020
Lafone L, Sidiropoulos TPH, Oulton RF, 2014, Hybrid Plasmonic Strip and Slot Waveguides for Deep Subwavelength Nanofocusing of TE and TM Modes, Conference on Lasers and Electro-Optics (CLEO), Publisher: IEEE, ISSN: 2160-9020
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