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ACS Photonics

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https://www.readbyqxmd.com/read/28540324/watt-level-continuous-wave-emission-from-a-bifunctional-quantum-cascade-laser-detector
#1
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
#2
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
#3
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
#4
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
#5
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/28255572/label-free-single-molecule-imaging-with-numerical-aperture-shaped-interferometric-scattering-microscopy
#6
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
#7
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
#8
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/28451625/optical-resonance-imaging-an-optical-analog-to-mri-with-sub-diffraction-limited-capabilities
#9
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
#10
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
#11
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
#12
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
https://www.readbyqxmd.com/read/27785456/gyroid-optical-metamaterials-calculating-the-effective-permittivity-of-multidomain-samples
#13
James A Dolan, Matthias Saba, Raphael Dehmel, Ilja Gunkel, Yibei Gu, Ulrich Wiesner, Ortwin Hess, Timothy D Wilkinson, Jeremy J Baumberg, Ullrich Steiner, Bodo D Wilts
Gold gyroid optical metamaterials are known to possess a reduced plasma frequency and linear dichroism imparted by their intricate subwavelength single gyroid morphology. The anisotropic optical properties are, however, only evident when a large individual gyroid domain is investigated. Multidomain gyroid metamaterials, fabricated using a polyisoprene-b-polystyrene-b-poly(ethylene oxide) triblock terpolymer and consisting of multiple small gyroid domains with random orientation and handedness, instead exhibit isotropic optical properties...
October 19, 2016: ACS Photonics
https://www.readbyqxmd.com/read/27785455/remote-sensing-with-commutable-monolithic-laser-and-detector
#14
Rolf Szedlak, Andreas Harrer, Martin Holzbauer, Benedikt Schwarz, Johannes Paul Waclawek, Donald MacFarland, Tobias Zederbauer, Hermann Detz, Aaron Maxwell Andrews, Werner Schrenk, Bernhard Lendl, Gottfried Strasser
The ubiquitous trend toward miniaturized sensing systems demands novel concepts for compact and versatile spectroscopic tools. Conventional optical sensing setups include a light source, an analyte interaction region, and a separate external detector. We present a compact sensor providing room-temperature operation of monolithic surface-active lasers and detectors integrated on the same chip. The differentiation between emitter and detector is eliminated, which enables mutual commutation. Proof-of-principle gas measurements with a limit of detection below 400 ppm are demonstrated...
October 19, 2016: ACS Photonics
https://www.readbyqxmd.com/read/27563688/harmonics-generation-by-surface-plasmon-polaritons-on-single-nanowires
#15
Anouk de Hoogh, Aron Opheij, Matthias Wulf, Nir Rotenberg, L Kuipers
We present experimental observations of visible wavelength second- and third-harmonic generation on single plasmonic nanowires of variable widths. We identify that near-infrared surface plasmon polaritons, which are guided along the nanowire, act as the source of the harmonics generation. We discuss the underlying mechanism of this nonlinear process, using a combination of spatially resolved measurements and numerical simulations to show that the visible harmonics are generated via a combination of both local and propagating plasmonic modes...
August 17, 2016: ACS Photonics
https://www.readbyqxmd.com/read/27517058/spatially-resolved-two-dimensional-infrared-spectroscopy-via-wide-field-microscopy
#16
Joshua S Ostrander, Arnaldo L Serrano, Ayanjeet Ghosh, Martin T Zanni
We report the first wide-field microscope for measuring two-dimensional infrared (2D IR) spectroscopic images. We concurrently collect more than 16 000 2D IR spectra, made possible by a new focal plane array detector and mid-IR pulse shaping, to generate hyperspectral images with multiple frequency dimensions and diffraction-limited spatial resolution. Both frequency axes of the spectra are collected in the time domain by scanning two pairs of femtosecond pulses using a dual acousto-optic modulator pulse shaper...
July 20, 2016: ACS Photonics
https://www.readbyqxmd.com/read/27347494/plasmonic-nanostars-as-efficient-broadband-scatterers-for-random-lasing
#17
Johannes Ziegler, Christian Wörister, Cynthia Vidal, Calin Hrelescu, Thomas A Klar
Huge spectral coverage of random lasing throughout the visible up to the infrared range is achieved with star-shaped gold nanoparticles ("nanostars"). As intrinsically broadband scattering centers, the nanostars are suspended in solutions of various laser dyes, forming randomly arranged resonators which support coherent laser modes. The narrow emission line widths of 0.13 nm or below suggest that gold nanostars provide an efficient coherent feedback for random lasers over an extensive range of wavelengths, all together spanning almost a full optical octave from yellow to infrared...
June 15, 2016: ACS Photonics
https://www.readbyqxmd.com/read/27331079/flexible-white-light-emitting-diodes-based-on-nitride-nanowires-and-nanophosphors
#18
Nan Guan, Xing Dai, Agnès Messanvi, Hezhi Zhang, Jianchang Yan, Eric Gautier, Catherine Bougerol, François H Julien, Christophe Durand, Joël Eymery, Maria Tchernycheva
We report the first demonstration of flexible white phosphor-converted light emitting diodes (LEDs) based on p-n junction core/shell nitride nanowires. GaN nanowires containing seven radial In0.2Ga0.8N/GaN quantum wells were grown by metal-organic chemical vapor deposition on a sapphire substrate by a catalyst-free approach. To fabricate the flexible LED, the nanowires are embedded into a phosphor-doped polymer matrix, peeled off from the growth substrate, and contacted using a flexible and transparent silver nanowire mesh...
April 20, 2016: ACS Photonics
https://www.readbyqxmd.com/read/27077075/anomalous-spectral-shift-of-near-and-far-field-plasmonic-resonances-in-nanogaps
#19
Anna Lombardi, Angela Demetriadou, Lee Weller, Patrick Andrae, Felix Benz, Rohit Chikkaraddy, Javier Aizpurua, Jeremy J Baumberg
The near-field and far-field spectral response of plasmonic systems are often assumed to be identical, due to the lack of methods that can directly compare and correlate both responses under similar environmental conditions. We develop a widely tunable optical technique to probe the near-field resonances within individual plasmonic nanostructures that can be directly compared to the corresponding far-field response. In tightly coupled nanoparticle-on-mirror constructs with nanometer-sized gaps we find >40 meV blue-shifts of the near-field compared to the dark-field scattering peak, which agrees with full electromagnetic simulations...
March 16, 2016: ACS Photonics
https://www.readbyqxmd.com/read/26937421/lasing-from-glassy-ge-quantum-dots-in-crystalline-si
#20
Martyna Grydlik, Florian Hackl, Heiko Groiss, Martin Glaser, Alma Halilovic, Thomas Fromherz, Wolfgang Jantsch, Friedrich Schäffler, Moritz Brehm
Semiconductor light-emitters compatible with standard Si integration technology (SIT) are of particular interest for overcoming limitations in the operating speed of microelectronic devices. Light sources based on group IV elements would be SIT-compatible, but suffer from the poor optoelectronic properties of bulk Si and Ge. Here we demonstrate that epitaxially grown Ge quantum dots (QDs) in a defect-free Si matrix show extraordinary optical properties if partially amorphized by Ge-ion bombardment (GIB). In contrast to conventional SiGe nanostructures, these QDs exhibit dramatically shortened carrier lifetimes and negligible thermal quenching of the photoluminescence (PL) up to room temperature...
February 17, 2016: ACS Photonics
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