The Experts below are selected from a list of 258 Experts worldwide ranked by ideXlab platform

I Y Dodin - One of the best experts on this subject based on the ideXlab platform.

  • restoring Geometrical Optics near caustics using sequenced metaplectic transforms
    arXiv: Optics, 2020
    Co-Authors: N A Lopez, I Y Dodin
    Abstract:

    Geometrical Optics (GO) is often used to model wave propagation in weakly inhomogeneous media and quantum-particle motion in the semiclassical limit. However, GO predicts spurious singularities of the wavefield near reflection points and, more generally, at caustics. We present a new formulation of GO, called metaplectic Geometrical Optics (MGO), that is free from these singularities and can be applied to any linear wave equation. MGO uses sequenced metaplectic transforms of the wavefield, corresponding to symplectic transformations of the ray phase space, such that caustics disappear in the new variables, and GO is reinstated. The Airy problem and the quantum harmonic oscillator are studied analytically using MGO for illustration. In both cases, the MGO solutions are remarkably close to the exact solutions and remain finite at cutoffs, unlike the usual GO solutions.

  • lagrangian Geometrical Optics of nonadiabatic vector waves and spin particles
    Physics Letters A, 2015
    Co-Authors: D E Ruiz, I Y Dodin
    Abstract:

    Abstract Linear vector waves, both quantum and classical, experience polarization-driven bending of ray trajectories and polarization dynamics that can be interpreted as the precession of the “wave spin”. Both phenomena are governed by an effective gauge Hamiltonian vanishing in leading-order Geometrical Optics. This gauge Hamiltonian can be recognized as a generalization of the Stern–Gerlach Hamiltonian that is commonly known for spin-1/2 quantum particles. The corresponding reduced Lagrangians for continuous nondissipative waves and their Geometrical-Optics rays are derived from the fundamental wave Lagrangian. The resulting Euler–Lagrange equations can describe simultaneous interactions of N resonant modes, where N is arbitrary, and lead to equations for the wave spin, which happens to be an ( N 2 − 1 ) -dimensional spin vector. As a special case, classical equations for a Dirac particle ( N = 2 ) are deduced formally, without introducing additional postulates or interpretations, from the Dirac quantum Lagrangian with the Pauli term. The model reproduces the Bargmann–Michel–Telegdi equations with added Stern–Gerlach force.

  • axiomatic Geometrical Optics abraham minkowski controversy and photon properties derived classically
    Physical Review A, 2012
    Co-Authors: I Y Dodin, N J Fisch
    Abstract:

    By restating Geometrical Optics within the eld-theoretical approach, the classical concept of a photon in arbitrary dispersive medium is introduced, and photon properties are calculated unambiguously. In particular, the canonical and kinetic momenta carried by a photon, as well as the two corresponding energy-momentum tensors of a wave, are derived straightforwardly from rst principles of Lagrangian mechanics. The Abraham-Minkowski controversy pertaining to the de nitions of these quantities is thereby resolved for linear waves of arbitrary nature, and corrections to the traditional formulas for the photon kinetic quantities are found. An application of axiomatic Geometrical Optics to electromagnetic waves is also presented as an example.

Yuehuan Wei - One of the best experts on this subject based on the ideXlab platform.

  • Geometrical Optics approximation of light scattering by large air bubbles
    Particuology, 2008
    Co-Authors: Jianqi Shen, Yuehuan Wei
    Abstract:

    Abstract For large spherical bubbles in water, Geometrical Optics approximation is considered a better method for calculating light scattering patterns. In this paper, the basic theory of Geometrical Optics approximation is clarified. The change of phase for bubbles is calculated when total reflection occurs, which is different from particles with relative refractive indices larger than 1. Verification of the method was achieved by assuming a spherical particle and comparing present results to Mie scattering and Debye calculation. Agreement with the Mie theory was excellent in all directions when the dimensionless size parameter is larger than 50. Limitations of the Geometrical Optics approximation are also discussed.

Giovanni Volpe - One of the best experts on this subject based on the ideXlab platform.

  • Computational toolbox for optical tweezers in the Geometrical Optics regime
    Biophotonics Congress: Optics in the Life Sciences Congress 2019 (BODA BRAIN NTM OMA OMP), 2019
    Co-Authors: Agnese Callegari, Mite Mijalkov, A. Burak Gököz, Giovanni Volpe
    Abstract:

    We provide a toolbox for the calculation of optical forces and torques on dielectric particles in the Geometrical Optics limit.

  • Computational toolbox for optical tweezers in Geometrical Optics
    Journal of The Optical Society of America B-optical Physics, 2015
    Co-Authors: Agnese Callegari, Mite Mijalkov, A. Burak Gököz, Giovanni Volpe
    Abstract:

    Optical tweezers have found widespread application in many fields, from physics to biology. Here, we explain in detail how optical forces and torques can be described within the Geometrical Optics approximation, and we show that this approximation provides reliable results in agreement with experiments for particles whose characteristic dimensions are larger than the wavelength of the trapping light. Furthermore, we provide an object-oriented software package implemented in MATLAB for the calculation of optical forces and torques in the Geometrical Optics regime: Optical Tweezers in Geometrical Optics (OTGO). We provide all source codes for OTGO as well as documentation and code examples—e.g., standard optical tweezers, optical tweezers with elongated particles, the windmill effect, and Kramers transitions between two optical traps—necessary to enable users to effectively employ it in their research.

Aleksandr V Timofeev - One of the best experts on this subject based on the ideXlab platform.

  • Geometrical Optics and the diffraction phenomenon
    Physics-Uspekhi, 2005
    Co-Authors: Aleksandr V Timofeev
    Abstract:

    This note outlines the principles of the Geometrical Optics of inhomogeneous waves whose description necessitates the use of complex values of the wave vector. Generalizing Geometrical Optics to inhomogeneous waves permits including in its scope the analysis of the diffraction phenomenon.

Jianqi Shen - One of the best experts on this subject based on the ideXlab platform.

  • Geometrical Optics approximation of light scattering by large air bubbles
    Particuology, 2008
    Co-Authors: Jianqi Shen, Yuehuan Wei
    Abstract:

    Abstract For large spherical bubbles in water, Geometrical Optics approximation is considered a better method for calculating light scattering patterns. In this paper, the basic theory of Geometrical Optics approximation is clarified. The change of phase for bubbles is calculated when total reflection occurs, which is different from particles with relative refractive indices larger than 1. Verification of the method was achieved by assuming a spherical particle and comparing present results to Mie scattering and Debye calculation. Agreement with the Mie theory was excellent in all directions when the dimensionless size parameter is larger than 50. Limitations of the Geometrical Optics approximation are also discussed.