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ACS Photonics

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https://www.readbyqxmd.com/read/28966933/visual-understanding-of-light-absorption-and-waveguiding-in-standing-nanowires-with-3d-fluorescence-confocal-microscopy
#1
Rune Frederiksen, Gozde Tutuncuoglu, Federico Matteini, Karen L Martinez, Anna Fontcuberta I Morral, Esther Alarcon-Llado
Semiconductor nanowires are promising building blocks for next-generation photonics. Indirect proofs of large absorption cross sections have been reported in nanostructures with subwavelength diameters, an effect that is even more prominent in vertically standing nanowires. In this work we provide a three-dimensional map of the light around vertical GaAs nanowires standing on a substrate by using fluorescence confocal microscopy, where the strong long-range disruption of the light path along the nanowire is illustrated...
September 20, 2017: ACS Photonics
https://www.readbyqxmd.com/read/28824931/core-shell-plasmonic-nanohelices
#2
Dolfine Kosters, Anouk de Hoogh, Hans Zeijlemaker, Hakkı Acar, Nir Rotenberg, L Kuipers
We introduce core-shell plasmonic nanohelices, highly tunable structures that have a different response in the visible for circularly polarized light of opposite handedness. The glass core of the helices is fabricated using electron beam induced deposition and the pure gold shell is subsequently sputter coated. Optical measurements allow us to explore the chiral nature of the nanohelices, where differences in the response to circularly polarized light of opposite handedness result in a dissymmetry factor of 0...
July 19, 2017: ACS Photonics
https://www.readbyqxmd.com/read/28868327/near-field-optical-drilling-of-sub-%C3%AE-pits-in-thin-polymer-films
#3
Tao Ding, Rohit Chikkaraddy, Jan Mertens, Jeremy J Baumberg
Under UV illumination, polymer films can undergo chain scission and contract. Using this effect, tightly focused laser light is shown to develop runaway near-field concentration that drills sub-100 nm pits through a thin film. This subwavelength photolithography can be controlled in real time by monitoring laser scatter from the evolving holes, allowing systematic control of the void diameter. Our model shows how interference between the substrate and film together with near-field focusing by the evolving crevice directs this formation and predicts minimum pit sizes in films of 100 nm thickness on gold substrates...
June 21, 2017: ACS Photonics
https://www.readbyqxmd.com/read/28781983/high-photocurrent-in-gated-graphene-silicon-hybrid-photodiodes
#4
Sarah Riazimehr, Satender Kataria, Rainer Bornemann, Peter Haring Bolívar, Francisco Javier Garcia Ruiz, Olof Engström, Andres Godoy, Max C Lemme
Graphene/silicon (G/Si) heterojunction based devices have been demonstrated as high responsivity photodetectors that are potentially compatible with semiconductor technology. Such G/Si Schottky junction diodes are typically in parallel with gated G/silicon dioxide (SiO2)/Si areas, where the graphene is contacted. Here, we utilize scanning photocurrent measurements to investigate the spatial distribution and explain the physical origin of photocurrent generation in these devices. We observe distinctly higher photocurrents underneath the isolating region of graphene on SiO2 adjacent to the Schottky junction of G/Si...
June 21, 2017: ACS Photonics
https://www.readbyqxmd.com/read/28670601/light-directed-tuning-of-plasmon-resonances-via-plasmon-induced-polymerization-using-hot-electrons
#5
Tao Ding, Jan Mertens, Anna Lombardi, Oren A Scherman, Jeremy J Baumberg
The precise morphology of nanoscale gaps between noble-metal nanostructures controls their resonant wavelengths. Here we show photocatalytic plasmon-induced polymerization can locally enlarge the gap size and tune the plasmon resonances. We demonstrate light-directed programmable tuning of plasmons can be self-limiting. Selective control of polymer growth around individual plasmonic nanoparticles is achieved, with simultaneous real-time monitoring of the polymerization process in situ using dark-field spectroscopy...
June 21, 2017: ACS Photonics
https://www.readbyqxmd.com/read/28670600/single-quantum-dot-with-microlens-and-3d-printed-micro-objective-as-integrated-bright-single-photon-source
#6
Sarah Fischbach, Alexander Schlehahn, Alexander Thoma, Nicole Srocka, Timo Gissibl, Simon Ristok, Simon Thiele, Arsenty Kaganskiy, André Strittmatter, Tobias Heindel, Sven Rodt, Alois Herkommer, Harald Giessen, Stephan Reitzenstein
Integrated single-photon sources with high photon-extraction efficiency are key building blocks for applications in the field of quantum communications. We report on a bright single-photon source realized by on-chip integration of a deterministic quantum dot microlens with a 3D-printed multilens micro-objective. The device concept benefits from a sophisticated combination of in situ 3D electron-beam lithography to realize the quantum dot microlens and 3D femtosecond direct laser writing for creation of the micro-objective...
June 21, 2017: ACS Photonics
https://www.readbyqxmd.com/read/28540324/watt-level-continuous-wave-emission-from-a-bifunctional-quantum-cascade-laser-detector
#7
Benedikt Schwarz, Christine A Wang, Leo Missaggia, Tobias S Mansuripur, Paul Chevalier, Michael K Connors, Daniel McNulty, Jeffrey Cederberg, Gottfried Strasser, Federico Capasso
Bifunctional active regions, capable of light generation and detection at the same wavelength, allow a straightforward realization of the integrated mid-infrared photonics for sensing applications. Here, we present a high performance bifunctional device for 8 μm capable of 1 W single facet continuous wave emission at 15 °C. Apart from the general performance benefits, this enables sensing techniques which rely on continuous wave operation, for example, heterodyne detection, to be realized within a monolithic platform and demonstrates that bifunctional operation can be realized at longer wavelength, where wavelength matching becomes increasingly difficult and that the price to be paid in terms of performance is negligible...
May 17, 2017: ACS Photonics
https://www.readbyqxmd.com/read/28470028/high-power-growth-robust-ingaas-inalas-terahertz-quantum-cascade-lasers
#8
Christoph Deutsch, Martin Alexander Kainz, Michael Krall, Martin Brandstetter, Dominic Bachmann, Sebastian Schönhuber, Hermann Detz, Tobias Zederbauer, Donald MacFarland, Aaron Maxwell Andrews, Werner Schrenk, Mattias Beck, Keita Ohtani, Jérôme Faist, Gottfried Strasser, Karl Unterrainer
We report on high-power terahertz quantum cascade lasers based on low effective electron mass InGaAs/InAlAs semiconductor heterostructures with excellent reproducibility. Growth-related asymmetries in the form of interface roughness and dopant migration play a crucial role in this material system. These bias polarity dependent phenomena are studied using a nominally symmetric active region resulting in a preferential electron transport in the growth direction. A structure based on a three-well optical phonon depletion scheme was optimized for this bias direction...
April 19, 2017: ACS Photonics
https://www.readbyqxmd.com/read/28470027/the-origin-and-limit-of-asymmetric-transmission-in-chiral-resonators
#9
Nikhil Parappurath, Filippo Alpeggiani, L Kuipers, Ewold Verhagen
We observe that the asymmetric transmission (AT) through photonic systems with a resonant chiral response is strongly related to the far-field properties of eigenmodes of the system. This understanding can be used to predict the AT for any resonant system from its complex eigenmodes. We find that the resonant chiral phenomenon of AT is related to, and is bounded by, the nonresonant scattering properties of the system. Using the principle of reciprocity, we determine a fundamental limit to the maximum AT possible for a single mode in any chiral resonator...
April 19, 2017: ACS Photonics
https://www.readbyqxmd.com/read/28523285/electrically-pumped-wavelength-tunable-gaas-quantum-dots-interfaced-with-rubidium-atoms
#10
Huiying Huang, Rinaldo Trotta, Yongheng Huo, Thomas Lettner, Johannes S Wildmann, Javier Martín-Sánchez, Daniel Huber, Marcus Reindl, Jiaxiang Zhang, Eugenio Zallo, Oliver G Schmidt, Armando Rastelli
We demonstrate the first wavelength-tunable electrically pumped source of nonclassical light that can emit photons with wavelength in resonance with the D2 transitions of (87)Rb atoms. The device is fabricated by integrating a novel GaAs single-quantum-dot light-emitting diode (LED) onto a piezoelectric actuator. By feeding the emitted photons into a 75 mm long cell containing warm (87)Rb vapor, we observe slow-light with a temporal delay of up to 3.4 ns. In view of the possibility of using (87)Rb atomic vapors as quantum memories, this work makes an important step toward the realization of hybrid-quantum systems for future quantum networks...
March 15, 2017: ACS Photonics
https://www.readbyqxmd.com/read/28345012/enhanced-telecom-emission-from-single-group-iv-quantum-dots-by-precise-cmos-compatible-positioning-in-photonic-crystal-cavities
#11
Magdalena Schatzl, Florian Hackl, Martin Glaser, Patrick Rauter, Moritz Brehm, Lukas Spindlberger, Angelica Simbula, Matteo Galli, Thomas Fromherz, Friedrich Schäffler
Efficient coupling to integrated high-quality-factor cavities is crucial for the employment of germanium quantum dot (QD) emitters in future monolithic silicon-based optoelectronic platforms. We report on strongly enhanced emission from single Ge QDs into L3 photonic crystal resonator (PCR) modes based on precise positioning of these dots at the maximum of the respective mode field energy density. Perfect site control of Ge QDs grown on prepatterned silicon-on-insulator substrates was exploited to fabricate in one processing run almost 300 PCRs containing single QDs in systematically varying positions within the cavities...
March 15, 2017: ACS Photonics
https://www.readbyqxmd.com/read/28944259/observing-plasmon-damping-due-to-adhesion-layers-in-gold-nanostructures-using-electron-energy-loss-spectroscopy
#12
Steven J Madsen, Majid Esfandyarpour, Mark L Brongersma, Robert Sinclair
Gold plasmonic nanostructures with several different adhesion layers have been studied with monochromated electron energy loss spectroscopy in the scanning transmission electron microscope (STEM-EELS) and with surface enhanced Raman spectroscopy (SERS). Compared to samples with no adhesion layer, those with 2nm of Cr or Ti show broadened, lower intensity plasmon peaks as measured with EELS. This broadening is observed in both optically active ("bright") and inactive ("dark") plasmon modes. When the former are probed with SERS, the signal enhancement factor is lower for samples with Cr or Ti, another indication of reduced plasmon resonance...
February 15, 2017: ACS Photonics
https://www.readbyqxmd.com/read/28255572/label-free-single-molecule-imaging-with-numerical-aperture-shaped-interferometric-scattering-microscopy
#13
Daniel Cole, Gavin Young, Alexander Weigel, Aleksandar Sebesta, Philipp Kukura
Our ability to optically interrogate nanoscopic objects is controlled by the difference between their extinction cross sections and the diffraction-limited area to which light can be confined in the far field. We show that a partially transmissive spatial mask placed near the back focal plane of a high numerical aperture microscope objective enhances the extinction contrast of a scatterer near an interface by approximately T(-1/2), where T is the transmissivity of the mask. Numerical-aperture-based differentiation of background from scattered light represents a general approach to increasing extinction contrast and enables routine label-free imaging down to the single-molecule level...
February 15, 2017: ACS Photonics
https://www.readbyqxmd.com/read/28239617/analytic-optimization-of-near-field-optical-chirality-enhancement
#14
Christian Kramer, Martin Schäferling, Thomas Weiss, Harald Giessen, Tobias Brixner
We present an analytic derivation for the enhancement of local optical chirality in the near field of plasmonic nanostructures by tuning the far-field polarization of external light. We illustrate the results by means of simulations with an achiral and a chiral nanostructure assembly and demonstrate that local optical chirality is significantly enhanced with respect to circular polarization in free space. The optimal external far-field polarizations are different from both circular and linear. Symmetry properties of the nanostructure can be exploited to determine whether the optimal far-field polarization is circular...
February 15, 2017: ACS Photonics
https://www.readbyqxmd.com/read/28239616/optimization-of-nanoparticle-based-sers-substrates-through-large-scale-realistic-simulations
#15
Diego M Solís, José M Taboada, Fernando Obelleiro, Luis M Liz-Marzán, F Javier García de Abajo
Surface-enhanced Raman scattering (SERS) has become a widely used spectroscopic technique for chemical identification, providing unbeaten sensitivity down to the single-molecule level. The amplification of the optical near field produced by collective electron excitations -plasmons- in nanostructured metal surfaces gives rise to a dramatic increase by many orders of magnitude in the Raman scattering intensities from neighboring molecules. This effect strongly depends on the detailed geometry and composition of the plasmon-supporting metallic structures...
February 15, 2017: ACS Photonics
https://www.readbyqxmd.com/read/28713845/impact-of-phonons-on-dephasing-of-individual-excitons-in-deterministic-quantum-dot-microlenses
#16
Tomasz Jakubczyk, Valentin Delmonte, Sarah Fischbach, Daniel Wigger, Doris E Reiter, Quentin Mermillod, Peter Schnauber, Arsenty Kaganskiy, Jan-Hindrik Schulze, André Strittmatter, Sven Rodt, Wolfgang Langbein, Tilmann Kuhn, Stephan Reitzenstein, Jacek Kasprzak
Optimized light-matter coupling in semiconductor nanostructures is a key to understand their optical properties and can be enabled by advanced fabrication techniques. Using in situ electron beam lithography combined with a low-temperature cathodoluminescence imaging, we deterministically fabricate microlenses above selected InAs quantum dots (QDs), achieving their efficient coupling to the external light field. This enables performing four-wave mixing microspectroscopy of single QD excitons, revealing the exciton population and coherence dynamics...
December 21, 2016: ACS Photonics
https://www.readbyqxmd.com/read/28451625/optical-resonance-imaging-an-optical-analog-to-mri-with-sub-diffraction-limited-capabilities
#17
Marco A Allodi, Peter D Dahlberg, Richard J Mazuski, Hunter C Davis, John P Otto, Gregory S Engel
We propose here optical resonance imaging (ORI), a direct optical analog to magnetic resonance imaging (MRI). The proposed pulse sequence for ORI maps space to time and recovers an image from a heterodyne-detected third-order nonlinear photon echo measurement. As opposed to traditional photon echo measurements, the third pulse in the ORI pulse sequence has significant pulse-front tilt that acts as a temporal gradient. This gradient couples space to time by stimulating the emission of a photon echo signal from different lateral spatial locations of a sample at different times, providing a widefield ultrafast microscopy...
December 21, 2016: ACS Photonics
https://www.readbyqxmd.com/read/28217716/electromagnetic-confinement-via-spin-orbit-interaction-in-anisotropic-dielectrics
#18
Alessandro Alberucci, Chandroth P Jisha, Lorenzo Marrucci, Gaetano Assanto
We investigate electromagnetic propagation in uniaxial dielectrics with a transversely varying orientation of the optic axis, the latter staying orthogonal everywhere in the propagation direction. In such a geometry, the field experiences no refractive index gradients, yet it acquires a transversely modulated Pancharatnam-Berry phase, that is, a geometric phase originating from a spin-orbit interaction. We show that the periodic evolution of the geometric phase versus propagation gives rise to a longitudinally invariant effective potential...
December 21, 2016: ACS Photonics
https://www.readbyqxmd.com/read/28042593/surface-lattice-resonances-for-enhanced-and-directional-electroluminescence-at-high-current-densities
#19
Yuriy Zakharko, Martin Held, Arko Graf, Tobias Rödlmeier, Ralph Eckstein, Gerardo Hernandez-Sosa, Bernd Hähnlein, Jörg Pezoldt, Jana Zaumseil
Hybrid photonic-plasmonic modes in periodic arrays of metallic nanostructures offer a promising trade-off between high-quality cavities and subdiffraction mode confinement. However, their application in electrically driven light-emitting devices is hindered by their sensitivity to the surrounding environment and to charge injecting metallic electrodes in particular. Here, we demonstrate that the planar structure of light-emitting field-effect transistor (LEFET) ensures undisturbed operation of the characteristic modes...
December 21, 2016: ACS Photonics
https://www.readbyqxmd.com/read/27785457/spatio-temporal-modeling-of-lasing-action-in-core-shell-metallic-nanoparticles
#20
J Cuerda, F J García-Vidal, J Bravo-Abad
Nanoscale laser sources based on single metallic nanoparticles (spasers) have attracted significant interest for their fundamental implications and technological potential. Here we theoretically investigate the spatio-temporal dynamics of lasing action in core-shell metallic nanoparticles that include optically pumped four-level gain media. By using detailed semiclassical simulations based on a time-domain generalization of the finite-element method, we study the evolution of the lasing dynamics when going from a spherical case to an elongated nanorod configuration...
October 19, 2016: ACS Photonics
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