The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

L C Kwek - One of the best experts on this subject based on the ideXlab platform.

C H Lai - One of the best experts on this subject based on the ideXlab platform.

  • effects of a squeezed vacuum reservoir on Geometric Phase
    Physical Review A, 2007
    Co-Authors: Zhisong Wang, Xunli Feng, L C Kwek, C H Lai
    Abstract:

    Geometric Phase, for a two-level atom in an electromagnetic field interacting with a squeezed-vacuum reservoir, is calculated by establishing connecting density matrices, describing an evolution of a quantum open system, with a nonunit vector ray in a complex projective Hilbert space. Because the Geometric Phase depends only on the smooth curve on this space, it is formulated entirely in terms of Geometric structures. The results show that the Geometric Phase for the squeezed-vacuum reservoir has fully different behavior in comparison with one for the normal vacuum reservoir.

Etienne Brasselet - One of the best experts on this subject based on the ideXlab platform.

  • Nonlinear unitary transformations of space-variant polarized light fields from self-induced Geometric-Phase optical elements
    Physical Review A, 2018
    Co-Authors: Nina Kravets, Etienne Brasselet
    Abstract:

    We propose to couple the optical orientational nonlinearities of liquid crystals with their ability to self-organize to tailor them to control space-variant-polarized optical fields in a nonlinear manner. Experimental demonstration is made using a liquid crystal light valve that behaves like a light-driven Geometric Phase optical element. We also unveil two original nonlinear optical processes, namely self-induced separability and nonseparability. These results contribute to the advancement of nonlinear singular optics that is still in its infancy despite 25 years of effort, which may foster the development of nonlinear protocols to manipulate high-dimensional optical information both in the classical and quantum regimes.

  • Dielectric Geometric Phase optical elements fabricated by femtosecond direct laser writing in photoresists
    Applied Physics Letters, 2017
    Co-Authors: Xuewen Wang, Etienne Brasselet, Aleksandr Kuchmizhak, Saulius Juodkazis
    Abstract:

    We propose to use a femtosecond direct laser writing technique to realize dielectric optical elements from photo-resist materials for the generation of structured light from purely Geometrical Phase transformations. This is illustrated by the fabrication and characterization of spin-to-orbital optical angular momentum couplers generating optical vortices of topological charge from 1 to 20. In addition, the technique is scalable and allows obtaining microscopic to macroscopic flat optics. These results thus demonstrate that direct 3D photopolymerization technology qualifies for the realization of spin-controlled Geometric Phase optical elements.

  • Geometric Phase shaping of terahertz vortex beams.
    Optics Letters, 2017
    Co-Authors: Amalya Minasyan, Etienne Brasselet, Clément Trovato, Jérôme Degert, Eric Freysz, Emmanuel Abraham
    Abstract:

    We propose a topological beam-shaping strategy of terahertz (THz) beams using Geometric Phase elements made of space-variant birefringent slabs. Quasi-monochromatic THz vortex beams are produced and characterized both in amplitude and Phase from the reconstructed real-time two-dimensional imaging of the electric field. Nonseparable superpositions of such vortex beams are also obtained and characterized by two-dimensional polarimetric analysis. These results emphasize the versatility of the spin-orbit electromagnetic toolbox to prepare on-demand structured light endowed with polarization-controlled orbital angular momentum content in the THz domain, which should find many uses in future THz technologies.

  • Reflective Spin-Orbit Geometric Phase from Chiral Anisotropic Optical Media
    Physical Review Letters, 2016
    Co-Authors: Mushegh Rafayelyan, Georgiy Tkachenko, Etienne Brasselet
    Abstract:

    We report on highly reflective spin orbit Geometric Phase optical elements based on a helicity preserving circular Bragg reflection phenomenon. First, we present a dynamical Geometric Phase experiment using a flat chiral Bragg mirror. Then, we show that shaping such a Geometric Phase allows the efficient spin orbit tailoring of light fields without the need to fulfill any condition on birefringent Phase retardation, in contrast to the case of transmission spin orbit optical elements. This is illustrated by optical vortex generation from chiral liquid crystal droplets in the Bragg regime that unveils spin orbit consequences of the droplet's curvature. Our results thus introduce a novel class of Geometric Phase elements " Bragg Berry " optical elements.

Vlatko Vedral - One of the best experts on this subject based on the ideXlab platform.

  • Geometric Phase induced by a cyclically evolving squeezed vacuum reservoir
    Physical Review Letters, 2006
    Co-Authors: Angelo Carollo, Massimo G Palma, Artur łozinski, Marcelo Franca Santos, Vlatko Vedral
    Abstract:

    We propose a new way to generate an observable Geometric Phase by means of a completely incoherent phenomenon. We show how to imprint a Geometric Phase to a system by adiabatically manipulating the environment with which it interacts. As a specific scheme, we analyze a multilevel atom interacting with a broadband squeezed vacuum bosonic bath. As the squeezing parameters are smoothly changed in time along a closed loop, the ground state of the system acquires a Geometric Phase. We also propose a scheme to measure such a Geometric Phase by means of a suitable polarization detection.

  • Geometric Phase in open systems.
    Physical Review Letters, 2003
    Co-Authors: Angelo Carollo, I. Fuentes-guridi, M. França Santos, Vlatko Vedral
    Abstract:

    We calculate the Geometric Phase associated with the evolution of a system subjected to decoherence through a quantum-jump approach. The method is general and can be applied to many different physical systems. As examples, two main sources of decoherence are considered: dephasing and spontaneous decay. We show that the Geometric Phase is completely insensitive to the former, i.e., it is independent of the number of jumps determined by the dephasing operator.

Zhisong Wang - One of the best experts on this subject based on the ideXlab platform.

  • effects of a squeezed vacuum reservoir on Geometric Phase
    Physical Review A, 2007
    Co-Authors: Zhisong Wang, Xunli Feng, L C Kwek, C H Lai
    Abstract:

    Geometric Phase, for a two-level atom in an electromagnetic field interacting with a squeezed-vacuum reservoir, is calculated by establishing connecting density matrices, describing an evolution of a quantum open system, with a nonunit vector ray in a complex projective Hilbert space. Because the Geometric Phase depends only on the smooth curve on this space, it is formulated entirely in terms of Geometric structures. The results show that the Geometric Phase for the squeezed-vacuum reservoir has fully different behavior in comparison with one for the normal vacuum reservoir.