The Experts below are selected from a list of 72528 Experts worldwide ranked by ideXlab platform
Haitao Liu - One of the best experts on this subject based on the ideXlab platform.
-
Intuitive Model of exceptional points in an optical whispering-gallery microcavity perturbed by nanoparticles
Physical Review A, 2020Co-Authors: Junda Zhu, Haitao Liu, Can Tao, Guoquan ZhangAbstract:Exceptional points (EPs) in the optical whispering-gallery-mode (WGM) microcavity perturbed by Rayleigh scatterers have shown great potential in the areas of on-chip chiral photonics and enhanced sensors, creating a huge demand for deep theoretical insight into the unique physical properties of EPs. Here we propose an Intuitive and first-principles-based Model to clarify the formation of the EPs in the WGM microcavity perturbed by two nanoparticles. The Model is constructed by considering a dynamical multiple-scattering process involving the clockwise and counterclockwise azimuthally propagating modes (APMs) at the nanoparticles. The complex resonance frequencies and resonant modes of the system can be comprehensively reproduced with the Model. The conditions for the determination of EPs are derived, and the system parameters at the EP can be quantitatively predicted. The Model unveils the relationship between the spatial chirality of the resonant modes near the EP and the scattering of APMs at the nanoparticles. The Model quantitatively predicts the difference between the APM coefficients within different azimuthal regions divided by the two nanoparticles, which were considered to be identical in previous theoretical formalisms, and it exhibits the contributions of the APMs, other than those considered in the Model, to forming the resonant modes. The proposition of the theoretical Model will benefit the investigations of EPs in WGM microcavities and their applications.
-
Impact of nanoparticle-induced scattering of an azimuthally propagating mode on the resonance of whispering gallery microcavities
Photonics Research, 2017Co-Authors: Junda Zhu, Ying Zhong, Haitao LiuAbstract:Optical whispering gallery microcavities with high-quality factors have shown great potential toward achieveing ultrahigh-sensitivity sensing up to a single molecule or nanoparticle, which raises a huge demand on a deep theoretical insight into the crucial phenomena such as the mode shift, mode splitting, and mode broadening in sensing experiments. Here we propose an Intuitive Model to analyze these phenomena from the viewpoint of the nanoparticle-induced multiple scattering of the azimuthally propagating mode (APM). The Model unveils explicit relations between these phenomena and the phase change and energy loss of the APM when scattered at the nanoparticle; the Model also explains the observed polarization-dependent preservation of one resonance and the particle-dependent redshift or blueshift. The Model indicates that the particle-induced coupling between the pair of unperturbed degenerate whispering gallery modes (WGMs) and the coupling between the WGMs and the free-space radiation modes, which are widely adopted in current theoretical formalisms, are realized via the reflection and scattering-induced free-space radiation of the APM, respectively, and additionally exhibits the contribution of cross coupling between the unperturbed WGMs and other different WGMs to forming the splitting resonant modes, especially for large particles.
-
Light scattering by metallic surfaces with subwavelength patterns
Physical Review B: Condensed Matter and Materials Physics, 2010Co-Authors: Haitao Liu, Philippe LalanneAbstract:We present a simple and Intuitive Model for analyzing the optical response of metallic surfaces patterned by arbitrary one-dimensional arrays of subwavelength sub- structures. In the present microscopic approach, the near-field response close to the surface is composed of a linear combination of elementary hybrid waves, which are shown to solely depend on the frequency and to be merely independent of the incident illumination and of the scatterer geometry. The Model is tested against fully vectorial computational results obtained for simple systems that can be handled numerically with fully vectorial methods and, in contrast to classical Models that solely rely on surface plasmon polaritons, the present Model is shown to be highly accurate over a broad spectral range below the plasma frequency of the metal.
Junda Zhu - One of the best experts on this subject based on the ideXlab platform.
-
Intuitive Model of exceptional points in an optical whispering-gallery microcavity perturbed by nanoparticles
Physical Review A, 2020Co-Authors: Junda Zhu, Haitao Liu, Can Tao, Guoquan ZhangAbstract:Exceptional points (EPs) in the optical whispering-gallery-mode (WGM) microcavity perturbed by Rayleigh scatterers have shown great potential in the areas of on-chip chiral photonics and enhanced sensors, creating a huge demand for deep theoretical insight into the unique physical properties of EPs. Here we propose an Intuitive and first-principles-based Model to clarify the formation of the EPs in the WGM microcavity perturbed by two nanoparticles. The Model is constructed by considering a dynamical multiple-scattering process involving the clockwise and counterclockwise azimuthally propagating modes (APMs) at the nanoparticles. The complex resonance frequencies and resonant modes of the system can be comprehensively reproduced with the Model. The conditions for the determination of EPs are derived, and the system parameters at the EP can be quantitatively predicted. The Model unveils the relationship between the spatial chirality of the resonant modes near the EP and the scattering of APMs at the nanoparticles. The Model quantitatively predicts the difference between the APM coefficients within different azimuthal regions divided by the two nanoparticles, which were considered to be identical in previous theoretical formalisms, and it exhibits the contributions of the APMs, other than those considered in the Model, to forming the resonant modes. The proposition of the theoretical Model will benefit the investigations of EPs in WGM microcavities and their applications.
-
Impact of nanoparticle-induced scattering of an azimuthally propagating mode on the resonance of whispering gallery microcavities
Photonics Research, 2017Co-Authors: Junda Zhu, Ying Zhong, Haitao LiuAbstract:Optical whispering gallery microcavities with high-quality factors have shown great potential toward achieveing ultrahigh-sensitivity sensing up to a single molecule or nanoparticle, which raises a huge demand on a deep theoretical insight into the crucial phenomena such as the mode shift, mode splitting, and mode broadening in sensing experiments. Here we propose an Intuitive Model to analyze these phenomena from the viewpoint of the nanoparticle-induced multiple scattering of the azimuthally propagating mode (APM). The Model unveils explicit relations between these phenomena and the phase change and energy loss of the APM when scattered at the nanoparticle; the Model also explains the observed polarization-dependent preservation of one resonance and the particle-dependent redshift or blueshift. The Model indicates that the particle-induced coupling between the pair of unperturbed degenerate whispering gallery modes (WGMs) and the coupling between the WGMs and the free-space radiation modes, which are widely adopted in current theoretical formalisms, are realized via the reflection and scattering-induced free-space radiation of the APM, respectively, and additionally exhibits the contribution of cross coupling between the unperturbed WGMs and other different WGMs to forming the splitting resonant modes, especially for large particles.
S Schrader - One of the best experts on this subject based on the ideXlab platform.
-
Morphology and conductivity of PEDOT/PSS films studied by scanning-tunneling microscopy
Chemical Physics Letters, 2004Co-Authors: S Timpanaro, Fredericus Johannes Touwslager, Martijn Kemerink, S SchraderAbstract:The influence of sorbitol on the nanometer-scale morphology of poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) is investigated by scanning–tunneling microscopy. In all investigated films relatively well-conducting PEDOT particles are observed, with typical sizes of 10–50 nm, that are embedded in a less conductive PSS matrix. Addition of sorbitol to the casting solution is found to enhance the clustering of the PEDOT particles into larger domains. The observed morphologies are correlated to the macroscopic conductivity of the films, using an Intuitive Model. In addition, the morphology in the top layer of the films was found to differ substantially from the bulk morphology.
K. Jang - One of the best experts on this subject based on the ideXlab platform.
-
Simple image-dipole method for photon scanning tunneling microscopy
Ultramicroscopy, 1995Co-Authors: Wonho Jhe, K. JangAbstract:Abstract We present a simple Intuitive Model of a Photon Scanning Tunneling Microscope (PSTM) using the image-dipole method of classical electrodynamics. In particular, the polarization dependences of the nanometric PSTM images can be qualitatively understood and agree well with recent experimental results.
Lieven Verschaffel - One of the best experts on this subject based on the ideXlab platform.
-
An empirical test of the impact of primitive Intuitive Models of operations on solving word problems with a multiplicative structure
Learning and Instruction, 1996Co-Authors: Erik De Corte, Lieven VerschaffelAbstract:Abstract A robust finding of past research is that the number types involved in a problem statement strongly affect the solution process and the difficulty level of problems with a multiplicative structure. To account for these number type effects Fischbein, Deri, Nello & Marino (1985) have put forward the theory of the primitive Intuitive Models of arithmetic operations. This theory specifies that every arithmetic operation (e.g., multiplication) is associated with a primitive Intuitive Model (e.g., repeated addition), which intervenes in the process of selecting the operation needed to solve a word problem. In an attempt to unravel the number type effects on solving multiplicative problems, a study was carried out in which student-generated word problems for given number sentences were used as data to test a series of hypotheses and predictions that were derived in a straightforward way from the theory of the Intuitive Models. Although the results are fairly consistent with the basic hypothesis of the theory, the investigation also shows that at a more specific level this theory cannot sufficiently account for a number of empirical observations. The study also points to the necessity of continued research aimed at a better understanding of the cognitive processes involved in students' Modeling of situations by multiplicative operations.
