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  • Anderson-like localization in disordered LN photonic crystal slab cavities
    ACS Photonics (IF 6.756) Pub Date : 2018-01-15
    Juan Pablo Vasco, Stephen Hughes

    We present a detailed theoretical study of the effects of structural disorder on LN photonic crystal slab cavities, ranging from short to long length scales (N=3-35 cavity lengths), using a fully three-dimensional Bloch mode expansion technique. We compute the optical density of states (DOS), quality factors and effective mode volumes of the cavity modes, with and without disorder, and compare with the localized modes of the corresponding disordered photonic crystal waveguide. We demonstrate how the quality factors and effective mode volumes saturate at a specific cavity length and become bounded by the corresponding values of the Anderson modes appearing in the disordered waveguide. By means of the intensity fluctuation criterion, we observe Anderson-like localization for cavity lengths larger than around L31, and show that the field confinement in the disordered LN cavities is mainly determined by the local characteristics of the structural disorder as long as the confinement region is far enough from the cavity mirrors and the effective mode localization length is much smaller than the cavity length; under this regime, the disordered cavity system becomes insensitive to changes in the cavity boundaries and a good agreement with the intensity fluctuation criterion is found for localization. Surprisingly, we find that the Anderson-like localized modes do not appear as new disorder-induced resonances in the main spectral region of the LN cavity modes, and, moreover, the disordered DOS enhancement is largest for the disordered waveguide system with the same length. These results are fundamentally interesting for applications such as lasing and cavity-QED, and provide new insights into the role of the boundary condition (e.g., open versus mirrors) on finite-size slow-light waveguides. They also point out the clear failure of using models based on the cavity boundaries/mirrors and a single slow-light Bloch mode to describe cavity systems with large N, which has been common practise.

    更新日期:2018-01-16
  • Non-blinking Quantum-Dot-Based Blue Light-Emitting Diodes with High Efficiency and Balanced Charge-Injection Process
    ACS Photonics (IF 6.756) Pub Date : 2018-01-15
    Qingli Lin, Lei Wang, Zhaohan Li, Huaibin Shen, Lijun Guo, Yanmin Kuang, Hongzhe Wang, Lin Song Li

    Blue non-blinking (>98% ‘on’ time) ZnCdSe/ZnS//ZnS quantum dots (QDs) with absolute fluorescence quantum yield (QY) of 92% (peak@472 nm) were synthesized via a low temperature nucleation and high temperature shell growth method. Such bright non-blinking ZnCdSe/ZnS//ZnS core/shell QDs exhibit not only good emission tunability in the blue-cyan range with corresponding wavelength from 450 to 495 nm, but also high absolute photoluminescence (PL) QY and superior chemical and photochemical stability. Highly efficient blue quantum dot-based light-emitting diodes (QLEDs) have been demonstrated by using non-blinking ZnCdSe/ZnS//ZnS QDs as emissive layer and the charge-injection balance within QD active layer were improved by introducing an non-conductive layer of poly(methyl methacrylate) (PMMA) between electron transport layer (ETL) and QD layer, where PMMA layer takes the role of coordinator to impede excessive electron flux. The best device exhibits outstanding features such as the maximum luminance of 14,100 cd/m2, current efficiency of 11.8 cd/A, and external quantum efficiency (EQE) of 16.2%. Importantly, the peak efficiency of the QLEDs with PMMA is achieved at ~ 1,000 cd/m2 and high EQE>12% can be sustained in the range of 100 to 3,000 cd/m2.

    更新日期:2018-01-16
  • Interference eraser experiment demonstrated with all-plasmonic which-path marker based on reverse spin Hall effect of light
    ACS Photonics (IF 6.756) Pub Date : 2018-01-15
    Aline Pham, Airong Zhao, Quanbo Jiang, Joel Bellessa, Cyriaque Genet, Aurélien Drezet

    We report on the reciprocal spin Hall effect of light in T-shaped nanoaperture arrays. Specifically, we demonstrate that the information tied to surface plasmons trajectories can be encoded into free-space spin-carrying photons. The functionality of the system to act as a circular polarizer is therefore implemented in an interference eraser experiment where the device is used as a which-path marker. Complementarity between the wave-like and particle-like behavior of surface plasmons is verified, hence further demonstrating the outlook for miniaturized optical elements towards on-chip quantum experiments. This work underscores the high potential of plasmonic devices in the realization of integrated polarization optics hence opening promising prospects for nanoscale optical communications and quantum photonic network.

    更新日期:2018-01-16
  • Universal linear-optical logic gate with maximal intensity contrast ratios
    ACS Photonics (IF 6.756) Pub Date : 2018-01-15
    Changnan Peng, Jiayu Li, Huimin Liao, Zhi Li, Chengwei Sun, Jianjun Chen, Qihuang Gong

    Linear-optical logic gates have the potential to be the bases of the next-generation information technology (IT) because of the low power consumption and rapid response. This study proposes a general theoretical model to obtain the optimal solutions for linear-optical logic gates. All common logic gates (AND, OR, NOT, NAND, NOR, XOR, and XNOR) are experimentally demonstrated with one single sample structure based on ultracompact plasmonic waveguides. The measured intensity contrast ratio between the output-logic “1” and “0” states reaches 28 dB for the OR gate and 9.4 dB for the AND gate, thereby approaching the theoretical maximum of infinity and 9.5 dB, respectively. The proposed logic gates provide uniform output intensities for identical output logics when the input logics are different. The measured intensity discrepancies are below 1% for the three output-logic “1” states of the OR gate and the three output-logic “0” states of the AND gate. This phenomenon is favored in practical applications and the cascading of logic gates. The proposed universal linear-optical logic gate with maximal intensity contrast ratios may find important future applications in the field of IT.

    更新日期:2018-01-16
  • Site-Selective, Two-Photon Plasmonic Nanofocusing on a Single Quantum Dot for Near-Room-Temperature Operation
    ACS Photonics (IF 6.756) Pub Date : 2018-01-12
    Su-Hyun Gong, Sejeong Kim, Je-Hyung Kim, Jong-Hoi Cho, Yong-Hoon Cho
    更新日期:2018-01-13
  • Multi-Terahertz sideband generation on an optical telecom carrier with a Quantum Cascade Laser
    ACS Photonics (IF 6.756) Pub Date : 2018-01-12
    Sarah Houver, Armand Lebreton, Alireza Mottaghizadeh, Maria Amanti, Carlo Sirtori, Gregoire Beaudoin, Isabelle Sagnes, Olivier Parillaud, Raffaele Colombelli, Juliette Mangeney, Robson Ferreira, Jérôme Tignon, Sukhdeep Dhillon

    Quantum Cascade Lasers (QCLs) are the principal semiconductor light sources for the mid-infrared (MIR) and terahertz (THz) spectral regions. However, up-converting their emission to the technologically mature telecom spectral region (1.3µm to 1.6µm) remains an important goal for applications. This would permit new QCL functionalities to be realized, such as stabilization and injection locking of the QCL emission to precise and low cost telecom frequency combs for spectroscopy. In this work, we demonstrate the up-conversion of the QCL emission to the telecom band at room temperature, using the QCLs’ inherent resonant optical nonlinearities. This is based on the generation of multi-THz sidebands on a telecom carrier, where a low power telecom beam at 1.55 µm is injected into the cavity of an InP-based MIR QCL (9 µm, 33 THz), giving rise to the nonlinear sum frequency at 1.3 µm. The results are supported by a theoretical model that highlights the giant enhancement of the nonlinear interaction through the resonant telecom excitation and the reduced role of phase matching. As well as potentially bringing important spectroscopic capabilities to QCLs, this compact and low power all-optical connection between the low-loss transmission windows of 1.3 µm and 1.55 µm would potentially permit QCLs to be applied as ultrafast wavelength shifters in fiber telecommunication networks.

    更新日期:2018-01-13
  • Fundamental Limitations to the Ultimate Kerr Nonlinear Performance of Plasmonic Waveguides
    ACS Photonics (IF 6.756) Pub Date : 2018-01-12
    Guangyuan Li, Martijn de Sterke, Stefano Palomba

    Plasmonic waveguides can greatly enhance nonlinear light-matter interactions through strong field confinement. However, achieving high performance nonlinear plasmonic devices remains challenging because of optical losses and material damage. Here we investigate the ultimate Kerr nonlinear performance of plasmonic waveguides. We account for optical damage by requiring that the local electric field intensity does not exceed the damage threshold of the nonlinear material. This allows us to factorize the fundamental limitations into those stemming from the constituent materials' linear and nonlinear properties, and from the mode characteristics. We define quality coefficients for the metal and for the nonlinear dielectric so that these materials can be selected appropriately, and illustrate their utility by application to surface plasmon polaritons (SPPs). We further propose the concept of nonlinear effectiveness in order to quantify a mode's ability to exploit the material's nonlinearity. We find that the full exploitation of the material's maximum nonlinearity requires a uniform field in addition to slow light effects. This is exemplified by the discovery that the maximum nonlinearity of Metal-Dielectric-Metal structures can be stronger than that of the bulk material. These counterintuitive insights provide deep understanding into the ultimate performance of nonlinear waveguides, and point to novel approaches to achieve practical, high performance nonlinear plasmonic devices.

    更新日期:2018-01-13
  • Few-cycle Surface Plasmon Polariton Generation by Rotating Wavefront Pulses
    ACS Photonics (IF 6.756) Pub Date : 2018-01-12
    Francesco Pisani, Luca Fedeli, Andrea Macchi

    A concept for the efficient generation of surface plasmon polaritons (SPPs) with a duration of very few cycles is presented. The scheme is based on grating coupling and laser pulses with wavefront rotation (WFR), so that the resonance condition for SPP excitation is satisfied only for a time window shorter than the driving pulse. The feasibility and robustness of the technique is investigated by means of simulations with realistic parameters. In optimal conditions, we find that a 29.5 fs pulse with 800 nm wavelength can excite a 3.8 fs SPP ( ~1.4 laser cycles) with a peak field amplitude 2.7 times the peak value for the laser pulse.

    更新日期:2018-01-13
  • Direct Observation of Ultrafast Exciton Dissociation in Lead Iodide Perovskite by 2D Electronic Spectroscopy
    ACS Photonics (IF 6.756) Pub Date : 2018-01-12
    Ajay Jha, Hong-Guang Duan, Vandana Tiwari, Pabitra K. Nayak, Henry J. Snaith, Michael Thorwart, R. J. Dwayne Miller
    更新日期:2018-01-12
  • In Vivo and in Situ Spectroscopic Imaging by a Handheld Stimulated Raman Scattering Microscope
    ACS Photonics (IF 6.756) Pub Date : 2018-01-12
    Chien-Sheng Liao, Pu Wang, Chih Yu Huang, Peng Lin, Gregory Eakins, R. Timothy Bentley, Rongguang Liang, Ji-Xin Cheng
    更新日期:2018-01-12
  • Anisotropic Thermal Magnetoresistance for an Active Control of Radiative Heat Transfer
    ACS Photonics (IF 6.756) Pub Date : 2018-01-12
    Ricardo M. Abraham Ekeroth, Philippe Ben-Abdallah, Juan Carlos Cuevas, Antonio García-Martín
    更新日期:2018-01-12
  • Femtosecond laser printing of single Ge and SiGe nanoparticles with electric and magnetic optical resonances
    ACS Photonics (IF 6.756) Pub Date : 2018-01-12
    Denis Zhigunov, Andrey B. Evlyukhin, Alexander Sergeevich Shalin, Urs Zywietz, Boris N. Chichkov

    Recently introduced femtosecond laser printing technique was further developed for the fabrication of crystalline single Ge and SiGe nanoparticles. Amorphous Ge and SiGe thin films deposited by e-beam evaporation on a transparent substrate were used as donors. The developed approach is based on laser-induced forward transfer process, which provides an opportunity of NP controlled positioning on different types of receiver substrates. The size of the generated nanoparticles can be varied from about 100 to 300 nm depending on the laser pulse energy and wavelength. The crystallinity and composition of nanoparticles are both confirmed by the Raman spectroscopy measurements. The experimental visible scattering spectra of single nanoparticles are found to be well coincident with theoretical simulations performed on the basis of Mie theory. It is demonstrated that Ge and SiGe nanoparticles are characterized by electric and magnetic dipole resonances in the visible and near-infrared spectral ranges, which is promising for photonic applications.

    更新日期:2018-01-12
  • Clocking the Ultrafast Electron Cooling in Anatase Titanium Dioxide Nanoparticles
    ACS Photonics (IF 6.756) Pub Date : 2018-01-11
    Edoardo Baldini, Tania Palmieri, Enrico Pomarico, Gerald Auböck, Majed Chergui

    The recent identification of strongly bound ex- citons in room temperature anatase TiO2 single crystals and nanoparticles underscores the importance of bulk many-body effects in samples used for applications. Here, for the first time, we unravel the interplay between many-body interactions and correlations in highly-excited anatase TiO2 nanoparticles using ultrafast two-dimensional deep-ultraviolet spectroscopy. With this approach, under non-resonant excitation, we disentangle the optical nonlinearities contributing to the bleach of the lowest direct exciton peak. This allows us to clock the ultrafast timescale of the hot electron thermalization in the conduction band with unprecedented temporal resolution, which we determine to be < 50 fs, due to the strong electron-phonon coupling in the material. Our findings call for the design of alternative resonant excitation schemes in photonics and nanotechnology.

    更新日期:2018-01-12
  • Highly Broadband Absorber Using Plasmonic Titanium Carbide (MXene)
    ACS Photonics (IF 6.756) Pub Date : 2018-01-10
    Krishnakali Chaudhuri, Mohamed Alhabeb, Zhuoxian Wang, Vladimir M. Shalaev, Yury Gogotsi, Alexandra Boltasseva

    Control of light transmission and reflection through nanostructured materials has led to demonstration of metamaterial absorbers that have augmented the performance of energy harvesting applications of several optoelectronic and nanophotonic systems. Here, for the first time, a broadband plasmonic metamaterial absorber is fabricated using two-dimensional titanium carbide (Ti3C2Tx) MXene. Arrays of nano disks made of Ti3C2Tx exhibit strong localized surface plasmon resonances at near-infrared frequencies. By exploiting the scattering enhancement at the resonances and the optical losses inherent to Ti3C2Tx MXene, high efficiency absorption (~90%) for a wide wavelength window of incident illumination (~1.55 µm) has been achieved.

    更新日期:2018-01-11
  • Interaction of Structured Light with a Chiral Plasmonic Metasurface: Giant Enhancement of Chiro-Optic Response
    ACS Photonics (IF 6.756) Pub Date : 2018-01-10
    Innem V.A.K. Reddy, Alexander Baev, Edward P. Furlani, Paras N. Prasad, Joseph W. Haus
    更新日期:2018-01-10
  • Isotropic Magnetic Purcell Effect
    ACS Photonics (IF 6.756) Pub Date : 2018-01-09
    Tianhua Feng, Wei Zhang, Zixian Liang, Yi Xu, Andrey E. Miroshnichenko
    更新日期:2018-01-10
  • Hybrid Plasmonic Bullseye Antennas for Efficient Photon Collection
    ACS Photonics (IF 6.756) Pub Date : 2018-01-09
    Sebastian K. H. Andersen, Simeon Bogdanov, Oksana Makarova, Yi Xuan, Mikhail Y. Shalaginov, Alexandra Boltasseva, Sergey I. Bozhevolnyi, Vladimir M. Shalaev
    更新日期:2018-01-10
  • Ab-initio Optimized Effective Potentials for Real Molecules in Optical Cavities: Photon Contributions to the Molecular Ground state
    ACS Photonics (IF 6.756) Pub Date : 2018-01-09
    Johannes Flick, Christian Schaefer, Michael Ruggenthaler, Heiko Appel, Angel Rubio

    We introduce a simple scheme to efficiently compute photon exchange-correlation contributions due to the coupling to transversal photons as formulated in the newly developed quantum-electrodynamical density functional theory (QEDFT). Our construction employs the optimized-effective potential (OEP) approach by means of the Sternheimer equation to avoid the explicit calculation of unoccupied states. We demonstrate the efficiency of the scheme by applying it to an exactly solvable GaAs quantum ring model system, a single azulene molecule, and chains of sodium dimers, all located in optical cavities and described in full real space. While the first example is a two-dimensional system and allows to benchmark the employed approximations, the latter two examples demonstrate that the correlated electron-photon interaction appreciably distorts the ground-state electronic structure of a real molecule. By using this scheme, we not only construct typical electronic observables, such as the electronic ground-state density, but also illustrate how photon observables, such as the photon number, and mixed electron-photon observables, e.g. electron-photon correlation functions, become accessible in a DFT framework. This work constitutes the first three-dimensional ab-initio calculation within the new QEDFT formalism and thus opens up a new computational route for the ab-initio study of correlated electron-photon systems in quantum cavities. Keywords: strong light-matter coupling, electronic structure, quantum-electrodynamical density-functional theory, optimized-effective potential

    更新日期:2018-01-10
  • Dye giant absorption and light confinement effects in porous Bragg microcavities
    ACS Photonics (IF 6.756) Pub Date : 2018-01-09
    Manuel Oliva-Ramirez, Jorge Gil-Rostra, Adam Cohen Simonsen, Francisco Yubero, Agustín R. Gonzalez-Elipe

    This work presents a simple experimental procedure to probe light confinement effects in photonic structures. Two types of porous 1D Bragg microcavities with two resonant peaks in the absorption gap were prepared by physical vapor deposition at oblique angle configurations and then infiltrated with a dye solution of increasing concentrations. The unusual position shift and intensity drop of the transmitted resonant peak observed when it was scanned through the dye absorption band have been accounted for by the effect of the light trapped at their optical defect layer. An experimentally observed giant absorption of the dye molecules and a strong anomalous dispersion in the refractive index of the solution are claimed as the reasons for the observed variations in the Bragg microcavity resonant feature. Determining the giant absorption of infiltrated dye solutions is proposed as a general and simple methodology to experimentally assess light trapping effects in porous photonic structures.

    更新日期:2018-01-10
  • Metasurface Approach to External Cloak and Designer Cavities
    ACS Photonics (IF 6.756) Pub Date : 2018-01-09
    Yineng Liu, Jinying Xu, shiyi xiao, Xianzhong Chen, Jensen Li

    Metasurface, with only single layer of artificial atoms for ease of fabrication, can become a practical surface-equivalent route to transformation optical (TO) applications. The previous design paradigm for a metasurface carpet cloak is based on straight-forward phase compensation, hampering more general wave manipulations. Here, we propose a theoretical approach in designing metasurface using the concept of complementary media as an intermediate step. The metasurface, effectively storing all the original information in TO media, enables specific TO applications which normally requires complementary media. A passive external metasurface cloak is numerically demonstrated here, which can hide an object on top of a reflective metasurface, mimicking a flat mirror. Furthermore, our scheme enables metasurfaces to be used to construct arbitrary standing waves on-demand, which will be useful for constructing tailor-made cavity modes, optical trapping and illusion-type TO applications, which can project holograms in addition to scattering cancellation.

    更新日期:2018-01-10
  • Omnidirectional and Broadband Light Absorption Enhancement in 2-D Photonic-structured Organic Solar Cells
    ACS Photonics (IF 6.756) Pub Date : 2018-01-09
    Weixia Lan, Yiwen Wang, Jai Singh, Furong Zhu

    The effect of 2-D photonic-structures on omnidirectional and broadband light absorption enhancement in organic solar cells (OSCs) is analysed using a combination of theoretical simulation and experimental optimization. The photonic structures in the active layers, with a blend system of poly[4,8-bis[(2-ethylhexyl)oxy] benzo[1,2-b:4,5-bA] dithiophene-2, 6-diyl][3-fluoro-2-[(2- ethylhexyl) carbonyl]thieno[3,4-b]-thiophenediyl] :[6,6]- phenyl-C70- butyric-acid-methyl-ester (PTB7:PC70BM), were prepared by the nanoimprint method. It shows that the 2-D photonic structures enable not only broadband but also omnidirectional absorption enhancements in the PTB7:PC70BM-based OSCs over a broader angle range of the incident light, leading to >11 % increase in the power conversion efficiency, as compared to the optimal planar control cells. A weak angular dependency on light absorption is a unique feature of the photonic-structured OSCs, which is useful for different applications.

    更新日期:2018-01-10
  • THz Generation and Detection by Fluorenone Based Organic Crystals
    ACS Photonics (IF 6.756) Pub Date : 2018-01-08
    Matteo Savoini, Lucas Huber, Herma Cuppen, Elsa Abreu, Martin Kubli, Martin J. Neugebauer, Yulong Duan, Paul Beaud, Jialiang Xu, Theo Rasing, Steven L. Johnson
    更新日期:2018-01-09
  • Lasing Interactions Disclose Hidden Modes of Necklace States in the Anderson Localized Regime
    ACS Photonics (IF 6.756) Pub Date : 2018-01-08
    Seung Ho Choi, Kyung Min Byun, Young L. Kim
    更新日期:2018-01-09
  • Plasmonic Cavity Coupling
    ACS Photonics (IF 6.756) Pub Date : 2018-01-08
    James T. Hugall, Anshuman Singh, Niek F. van Hulst
    更新日期:2018-01-09
  • Searching for Hidden Perovskite Materials for Photovoltaic Systems by Combining Data Science and First Principle Calculations
    ACS Photonics (IF 6.756) Pub Date : 2018-01-08
    Keisuke Takahashi, Lauren Takahashi, Itsuki Miyazato, Yuzuru Tanaka
    更新日期:2018-01-09
  • Topological Insulator Particles As Optically Induced Oscillators: Toward Dynamical Force Measurements and Optical Rheology
    ACS Photonics (IF 6.756) Pub Date : 2018-01-08
    W. H. Campos, J. M. Fonseca, V. E. de Carvalho, J. B. S. Mendes, M. S. Rocha, W. A. Moura-Melo
    更新日期:2018-01-08
  • High internal quantum efficiency ultraviolet emission from phase-transition cubic GaN integrated on nanopatterned Si(100).
    ACS Photonics (IF 6.756) Pub Date : 2018-01-08
    Richard Liu, Richard D. Schaller, ChangQiang Chen, Can Bayram

    Ultraviolet emission characteristics of cubic (c-) GaN enabled through hexagonal-to-cubic phase transition are reported. Substrate patterning and material growth are shown to affect phase purity and emission characteristics of c-GaN as studied by electron backscatter diffraction and photo- and cathodo- luminescence, respectively. Raman study shows a tensile strain in the c-GaN. Time-resolved photoluminescence reveals c-GaN band edge emission decay time of 11 ps. The ultraviolet emissions from both phases of GaN are linearly polarized in the same direction, which is along the and directions of hexagonal GaN and c-GaN, respectively. Temperature-dependent (5.7 K to 280 K) cathodoluminescence studies reveal an internal quantum efficiency of ~ 29% at room temperature along with intrinsic and extrinsic defect energy levels of ~124 and ~344 meV, respectively, of the phase-transition c-GaN. Using the IQE value and carrier decay lifetime, a radiative lifetime of 38 ps is extracted. Overall, photonic properties of phase-transition c-GaN and their dependence on substrate patterning and material growth are reported.

    更新日期:2018-01-08
  • A route to superior performance of a nanoplasmonic biosensor: consideration of both photonic and mass transport aspects
    ACS Photonics (IF 6.756) Pub Date : 2018-01-08
    Barbora Špačková, Nicholas Scott Scott Lynn Jr., Hana Šípová, Jiří Slabý, Jiri Homola

    Optical biosensors based on plasmonic nanostructures present a promising alternative to conventional biosensing methods and provide unmatched possibilities for miniaturization and high-throughput analysis. Previous works on the topic, however, have been overwhelmingly directed towards elucidating the optical performance of such sensors, with little emphasis on the topic of mass transport. To date, there exists no examination, experimental nor theoretical, of the bioanalytical performance of such sensors (in terms of detection limits) that simultaneously addresses both optical and mass transport aspects in a quantitative manner. In this work we present a universal model that describes the smallest concentration that can be detected by a nanoplasmonic biosensor. Accounting for both optical and mass transport aspects, this model establishes a relationship between bioanalytical performance and the biosensor's design parameters. We employ the model to optimize the performance of a nanoplasmonic DNA biosensor consisting of randomly distributed gold nanorods on a glass substrate. Through both experimental and theoretical results, we show that the proper design of a nanostructured sensing substrate is one that maximizes mass transport efficiency while preserving the quality of the optical readout. All results are compared with those obtained using a conventional SPR biosensor. We show that an optimized nanoplasmonic substrate allows for the detection of DNA at concentrations of an order of magnitude lower with respect to a SPR biosensor.

    更新日期:2018-01-08
  • Microscopic observation of low efficiency in green light-emitting diodes
    ACS Photonics (IF 6.756) Pub Date : 2018-01-08
    Young-Chul Leem, Sang-Youp Yim

    The low efficiency of green light-emitting diodes (LEDs), a phenomenon known as the green gap, is a key obstacle hindering the application of LEDs as next-generation light sources to pioneer a plethora of new applications in the optical, medical, and communication sectors. Based on a microscopic photoluminescence analysis of green GaN-based multiple quantum wells, we find that In-enriched emission clusters on the submicron scale, previously thought to be efficient luminescent centers, do not emit light effectively. Such emission clusters can localize an excessively large amount of carriers, leading to the subsequent occurrence of vigorous nonradiative recombination processes. We also observe that the effective volume of the LED active region is significantly reduced, possibly because the generation of these In-enriched clusters via metastable phase separation significantly degrades the surrounding crystal quality. The microscopic analysis of luminescent clusters gives insight into the low efficiency of green LEDs, which may guide future directions for the development of LEDs.

    更新日期:2018-01-08
  • Active Tuning of Strong Coupling States between Dye Excitons and Localized Surface Plasmons via Electrochemical Potential Control
    ACS Photonics (IF 6.756) Pub Date : 2018-01-07
    Fumiya Kato, Hiro Minamimoto, Fumika Nagasawa, Yuko Yamamoto, Tamitake Itoh, Kei Murakoshi

    Here we report the tuning of a number of excited dye molecules that were strongly coupled with the localized surface plasmons (LSPs) of Au nanostructures by electrochemical potential control. Using the redox state-tuned dye molecules and several types of metal nanostructures with distinct LSP energies, active control of the high coupling strength was achieved via an electrochemical potential-based control method. One interesting finding of the present work is that the parabolic behavior of the coupling strength in the range between 0.1 and 0.27 eV is dependent on the electrochemical potential; this has not been observed previously. Anti-crossing plots showing the energies of the upper and lower states of the coupling to the LSP energy suggest that the number of dye molecules contained in the cavity-confined LSP field is controlled not only by the redox states of the dye molecules but also by the interactions between the dyes and the metal surfaces. The present finding provides a novel route to control of light-matter interaction regarding the energy of electrons in metals and molecules, defined by absolute potential, i.e., electrochemical potential.

    更新日期:2018-01-07
  • Efficient Optical Amplification in the Nanosecond Regime from Formamidinium Lead Iodide Nanocrystals
    ACS Photonics (IF 6.756) Pub Date : 2018-01-07
    Paris Papagiorgis, Andreas Manoli, Loredana Protesescu, Charis Achilleos, Miltiadis Violaris, Konstantinos Nicolaides, Theodossis Trypiniotis, Maryna I. Bodnarchuk, Maksym V. Kovalenko, Andreas Othonos, Grigorios Itskos

    Lead halide perovskites nanocrystals (NCs) were recently found to exhibit extraordinary optical amplification properties. The great majority of such studies, implemented ultrashort photon pulses in the femtosecond regime to initiate the stimulated emission process. Yet the realization of practical lasing applications based on such materials is crucially dependent on their ability to sustain optical amplification at significantly longer timescales, at which major losses associated with spontaneous emission and non-radiative recombination occur. Herein we demonstrate highly efficient amplified spontaneous emission (ASE) from closed-packed films of formamidinium lead iodide perovskite (FAPbI3) NCs under excitation in the nanosecond regime. Systematic optimization of the NCs processing and thermal treatment, yields solids that exhibit high ASE net modal gain up to 604 cm-1 and nearly-temperature insensitive ASE thresholds with room temperature values as low as 140 μJ cm-2. The efficient optical amplification using excitation pulses comparable to the exciton lifetime combined with the excellent chemical durability and air stability of FAPbI3 NCs renders them as outstanding gain media for continuous wave lasers in the red and near-infrared.

    更新日期:2018-01-07
  • Fabrication of Highly Metallic TiN Films by Pulsed Laser Deposition Method for Plasmonic Applications
    ACS Photonics (IF 6.756) Pub Date : 2018-01-05
    Ramu Pasupathi Sugavaneshwar, Satoshi Ishii, Thang Duy Dao, Akihiko Ohi, Toshihide Nabatame, Tadaaki Nagao
    更新日期:2018-01-06
  • Generated Carrier Dynamics in V-Pit-Enhanced InGaN/GaN Light-Emitting Diode
    ACS Photonics (IF 6.756) Pub Date : 2018-01-05
    Idris A. Ajia, Paul R. Edwards, Yusin Pak, Ermek Belekov, Manuel A. Roldan, Nini Wei, Zhiqiang Liu, Robert W. Martin, Iman S. Roqan
    更新日期:2018-01-06
  • Broadband Omnidirectional Diffuse Mirrors with Hierarchically Designed All-Dielectric Surfaces
    ACS Photonics (IF 6.756) Pub Date : 2018-01-05
    Yoon-Jong Moon, Jin-Young Na, Yong Hyun Park, Soo Bin Kim, Sang Woon Lee, Sun-Kyung Kim
    更新日期:2018-01-06
  • 更新日期:2018-01-06
  • Interferometric Scattering Microscopy with Polarization-Selective Dual Detection Scheme: Capturing the Orientational Information of Anisotropic Nanometric Objects
    ACS Photonics (IF 6.756) Pub Date : 2018-01-05
    Il-Buem Lee, Hyeon-Min Moon, Jong-Hyeon Joo, Kyoung-Hoon Kim, Seok-Cheol Hong, Minhaeng Cho
    更新日期:2018-01-05
  • Holographic Resonant Laser Printing of Metasurfaces Using Plasmonic Template
    ACS Photonics (IF 6.756) Pub Date : 2018-01-05
    Marcus S. Carstensen, Xiaolong Zhu, Oseze Esther Iyore, N. Asger Mortensen, Uriel Levy, Anders Kristensen
    更新日期:2018-01-05
  • Highly Reliable Low-Threshold InAs Quantum Dot Lasers on On-Axis (001) Si with 87% Injection Efficiency
    ACS Photonics (IF 6.756) Pub Date : 2018-01-05
    Daehwan Jung, Zeyu Zhang, Justin Norman, Robert Herrick, M. J. Kennedy, Pari Patel, Katherine Turnlund, Catherine Jan, Yating Wan, Arthur C. Gossard, John E. Bowers
    更新日期:2018-01-05
  • Topological engineering of interfacial optical Tamm states for highly-sensitive near-singular-phase optical detection
    ACS Photonics (IF 6.756) Pub Date : 2018-01-04
    Yoichiro Tsurimaki, Jonathan K Tong, Victor N Boriskin, Alexander Semenov, Mykola I Ayzatsky, Yuri P Мachekhin, Gang Chen, Svetlana V. Boriskina

    We developed planar multilayered photonic-plasmonic structures, which support topologically protected optical states on the interface between metal and dielectric materials, known as optical Tamm states. Coupling of incident light to the Tamm states can result in perfect absorption within one of several narrow frequency bands, which is accompanied by a singular behavior of the phase of electromagnetic field. In the case of near-perfect absorptance, very fast local variation of the phase can still be engineered. In this work, we theoretically and experimentally demonstrate how these drastic phase changes can improve sensitivity of optical sensors. A planar Tamm absorber was fabricated and used to demonstrate remote near-singular-phase temperature sensing with an over an order of magnitude improvement in sensor sensitivity and over two orders of magnitude improvement in the figure of merit over the standard approach of measuring shifts of resonant features in the reflectance spectra of the same absorber. Our experimentally demonstrated phase-to-amplitude detection sensitivity improvement nearly doubles that of state-of-the-art nano-patterned plasmonic singular-phase detectors, with further improvements possible via more precise fabrication. Tamm perfect absorbers form the basis for robust planar sensing platforms with tunable spectral characteristics, which do not rely on low-throughput nano-patterning techniques.

    更新日期:2018-01-05
  • On-chip spectropolarimetry by fingerprinting with random surface arrays of nanoparticles
    ACS Photonics (IF 6.756) Pub Date : 2018-01-03
    Yiting Chen, Fei Ding, Victor Coello, Sergey I Bozhevolnyi

    Optical metasurfaces revolutionized the approach to mould the propagation of light by enabling simultaneous control of the light phase, momentum, amplitude and polarization. Thus, instantaneous spectropolarimetry became possible by conducting parallel intensity measurements of differently diffracted optical beams. Various implementations of this very important functionality have one feature in common - the determination of wavelength utilizes dispersion of the diffraction angle, requiring tracking the diffracted beams in space. Realization of on-chip spectropolarimetry calls thereby for conceptually different approaches. In this work, we demonstrate that random nanoparticle arrays on metal surfaces, enabling strong multiple scattering of surface plasmon polaritons (SPPs), produce upon illumination complicated SPP scattered patterns, whose angular spectra are uniquely determined by the polarization and wavelength of light, representing thereby spectropolarimetric fingerprints. Using μm-sized circular arrays of randomly distributed nm-sized gold nanoparticles (density ~ 75 µm-2) fabricated on gold films, we measure angular distributions of scattered SPP waves using the leakage radiation microscopy and find that the angular SPP spectra obtained for normally incident light beams different in wavelength and/or polarization are distinctly different. Our approach allows one to realize on-chip spectropolarimetry by fingerprinting using surface nanostructures fabricated with simple one-step electron-beam lithography.

    更新日期:2018-01-04
  • Comprehensive study of plasmonic materials in the visible and near-infrared: Linear, refractory, and nonlinear optical properties
    ACS Photonics (IF 6.756) Pub Date : 2018-01-03
    Gelon Albrecht, Monika Ubl, Stefan Kaiser, Harald Giessen, Mario Hentschel

    Plasmonic nanostructures are used today for a variety of applications. Choosing the best suited plasmonic material for a specific application depends on several criteria, such as chemical and thermal stability, bulk plasma frequency, nonlinear response, and fabrication constrains. To provide a comprehensive summary, we compare these properties for eight different plasmonic materials, namely Ag, Al, Au, Cu , Mg, Ni, Pd, and Pt. All these materials can be fabricated with electron beam lithography and subsequent evaporation of the desired material. Firstly, we heated rod-antenna type nanostructures made from these materials up to 1100°C in air and investigated their linear optical response. Most structures lose their plasmonic properties at temperatures far below the melting point of the respective material. Gold, silver, and platinum structurally deform, whereas the other materials appear to chemically degrade. Secondly, to improve the thermal stability, structures with a 4nm thin Al2O3 capping layer are fabricated. The thermal stability is significantly increased with the capping layer for all materials except for copper and magnesium. Lastly, the laser damage threshold is investigated for silver, aluminum, gold, and copper, which exhibit high nonlinear optical susceptibilities and are therefore particularly interesting for nonlinear optical applications.

    更新日期:2018-01-04
  • Antimatched Electromagnetic Metasurfaces for Broadband Arbitrary Phase Manipulation in Reflection
    ACS Photonics (IF 6.756) Pub Date : 2018-01-03
    Odysseas Tsilipakos, Thomas Koschny, Costas M. Soukoulis

    Metasurfaces impart phase discontinuities on impinging electromagnetic waves that are typically limited to 0-2π. Here, we demonstrate that multi-resonant metasurfaces can break free from this limitation and supply arbitrarily-large, tunable time delays over ultra-wide bandwidths. As such, ultra-thin metasurfaces can act as the equivalent of thick bulk structures by emulating the multiple geometric resonances of three-dimensional systems which originate from phase accumulation with effective material resonances implemented on the surface itself via suitable subwavelength meta-atoms. We describe a constructive procedure for defining the required sheet admittivities of such metasurfaces. Importantly, the proposed approach provides an exactly linear phase response so that broadband pulses can experience the desired group delay without any distortion of the pulse shape. We focus on operation in reflection by exploiting an antimatching condition, satisfied by interleaved electric and magnetic Lorentzian resonances in the surface admittivities, which completely zeroes out transmission through the metasurface. As a result, the proposed metasurfaces can perfectly reflect a broadband pulse imparting a prescribed group delay. The group delay can be tuned by modifying the implemented resonances, thus opening up diverse possibilities in the temporal applications of metasurfaces.

    更新日期:2018-01-04
  • Launching and Control of Graphene Plasmons by Nanoridge Structures
    ACS Photonics (IF 6.756) Pub Date : 2018-01-03
    Sanpon Vantasin, Yoshito Y. Tanaka, Tsutomu Shimura
    更新日期:2018-01-03
  • Si-Based GeSn Lasers with Wavelength Coverage of 2–3 μm and Operating Temperatures up to 180 K
    ACS Photonics (IF 6.756) Pub Date : 2017-12-29
    Joe Margetis, Sattar Al-Kabi, Wei Du, Wei Dou, Yiyin Zhou, Thach Pham, Perry Grant, Seyed Ghetmiri, Aboozar Mosleh, Baohua Li, Jifeng Liu, Greg Sun, Richard Soref, John Tolle, Mansour Mortazavi, Shui-Qing Yu
    更新日期:2017-12-31
  • Surface-Passivated AlGaN Nanowires for Enhanced Luminescence of Ultraviolet Light Emitting Diodes
    ACS Photonics (IF 6.756) Pub Date : 2017-12-29
    Haiding Sun, Mohammad Khaled Shakfa, Mufasila Mumthaz Muhammed, Bilal Janjua, Kuang-Hui Li, Ronghui Lin, Tien Khee Ng, Iman S. Roqan, Boon S. Ooi, Xiaohang Li
    更新日期:2017-12-31
  • Tunable Subnanometer Gap Plasmonic Metasurfaces
    ACS Photonics (IF 6.756) Pub Date : 2017-12-27
    Dennis Doyle, Nicholas Charipar, Christos Argyropoulos, Scott A. Trammell, Rafaela Nita, Jawad Naciri, Alberto Piqué, Joseph B. Herzog, Jake Fontana
    更新日期:2017-12-27
  • Three-Dimensional Multipole Rotation in Spherical Silver Nanoparticles Observed by Cathodoluminescence
    ACS Photonics (IF 6.756) Pub Date : 2017-12-26
    Zac Thollar, Carl Wadell, Taeko Matsukata, Naoki Yamamoto, Takumi Sannomiya
    更新日期:2017-12-27
  • Long-Range Transport of Organic Exciton-Polaritons Revealed by Ultrafast Microscopy
    ACS Photonics (IF 6.756) Pub Date : 2017-12-26
    Georgi Gary Rozenman, Katherine Akulov, Adina Golombek, Tal Schwartz
    更新日期:2017-12-27
  • meV Resolution in Laser-Assisted Energy-Filtered Transmission Electron Microscopy
    ACS Photonics (IF 6.756) Pub Date : 2017-12-26
    Enrico Pomarico, Ivan Madan, Gabriele Berruto, Giovanni Maria Vanacore, Kangpeng Wang, Ido Kaminer, F. Javier García de Abajo, Fabrizio Carbone
    更新日期:2017-12-27
  • Active Control of Surface Plasmon–Emitter Strong Coupling
    ACS Photonics (IF 6.756) Pub Date : 2017-12-22
    Antti J. Moilanen, Tommi K. Hakala, Päivi Törmä
    更新日期:2017-12-22
  • Ultra-narrow Line Width Polarization-Insensitive Filter Using a Symmetry-Breaking Selective Plasmonic Metasurface
    ACS Photonics (IF 6.756) Pub Date : 2017-12-22
    Yash D. Shah, James Grant, Danni Hao, Mitchell Kenney, Vincenzo Pusino, David R. S. Cumming
    更新日期:2017-12-22
  • 更新日期:2017-12-22
  • How Dark Are Radial Breathing Modes in Plasmonic Nanodisks?
    ACS Photonics (IF 6.756) Pub Date : 2017-12-22
    Franz-Philipp Schmidt, Arthur Losquin, Ferdinand Hofer, Andreas Hohenau, Joachim R. Krenn, Mathieu Kociak
    更新日期:2017-12-22
  • Nanoscale Switching of Near-Infrared Hot Spots in Plasmonic Oligomers Probed by Two-Photon Absorption in Photopolymers
    ACS Photonics (IF 6.756) Pub Date : 2017-12-22
    Yinping Zhang, Guillaume Demesy, Mohamed Haggui, Davy Gérard, Jérémie Béal, Stephanie Dodson, Qihua Xiong, Jérome Plain, Nicolas Bonod, Renaud Bachelot
    更新日期:2017-12-22
  • Selective Third-Harmonic Generation by Structured Light in Mie-Resonant Nanoparticles
    ACS Photonics (IF 6.756) Pub Date : 2017-12-22
    Elizaveta V. Melik-Gaykazyan, Sergey S. Kruk, Rocio Camacho-Morales, Lei Xu, Mohsen Rahmani, Khosro Zangeneh Kamali, Aristeidis Lamprianidis, Andrey E. Miroshnichenko, Andrey A. Fedyanin, Dragomir N. Neshev, Yuri S. Kivshar
    更新日期:2017-12-22
  • Interplay of Cascaded Raman- and Brillouin-like Scattering in Nanostructured Optical Waveguides
    ACS Photonics (IF 6.756) Pub Date : 2017-12-22
    Roman E. Noskov, Johannes R. Koehler, Andrey A. Sukhorukov
    更新日期:2017-12-22
  • Integration of Nanoscale Light Emitters and Hyperbolic Metamaterials: An Efficient Platform for the Enhancement of Random Laser Action
    ACS Photonics (IF 6.756) Pub Date : 2017-12-21
    Hung-I Lin, Kun-Ching Shen, Yu-Ming Liao, Yao-Hsuan Li, Packiyaraj Perumal, Golam Haider, Bo Han Cheng, Wei-Cheng Liao, Shih-Yao Lin, Wei-Ju Lin, Tai-Yuan Lin, Yang-Fang Chen
    更新日期:2017-12-21
  • Relaxation of Plasmon-Induced Hot Carriers
    ACS Photonics (IF 6.756) Pub Date : 2017-12-20
    Jun G. Liu, Hui Zhang, Stephan Link, Peter Nordlander
    更新日期:2017-12-21
  • Three-Dimensional Resolvable Plasmonic Concentric Compound Lens: Approaching the Axial Resolution from Microscale to Nanoscale
    ACS Photonics (IF 6.756) Pub Date : 2017-12-20
    Kai-Hao Chang, Yen-Chun Chen, Wen-Hao Chang, Po-Tsung Lee
    更新日期:2017-12-21
  • 更新日期:2017-12-21
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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