The Experts below are selected from a list of 4260 Experts worldwide ranked by ideXlab platform
Benjamin Canuel - One of the best experts on this subject based on the ideXlab platform.
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a marginally stable optical resonator for enhanced atom interferometry
Journal of Physics B, 2017Co-Authors: Isabelle Riou, Nicolas Mielec, Andrea Bertoldi, Benjamin Canuel, Arnaud Landragin, G Lefevre, Marco Prevedelli, Philippe Bouyer, R. GeigerAbstract:We propose a marginally stable optical resonator suitable for atom interferometry. The resonator geometry is based on two flat mirrors at the focal planes of a lens that produces the large Beam Waist required to coherently manipulate cold atomic ensembles. Optical gains of about 100 are achievable using optics with part-per-thousand losses. The resulting power build-up will allow for enhanced coherent manipulation of the atomic wavepackets such as large separation Beamsplitters. We study the effect of longitudinal misalignments and assess the robustness of the resonator in terms of intensity and phase profiles of the intra-cavity field. We also study how to implement atom interferometry based on Large Momentum Transfer Bragg diffraction in such a cavity.
Miles J Padgett - One of the best experts on this subject based on the ideXlab platform.
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divergence of an orbital angular momentum carrying Beam upon propagation
arXiv: Quantum Physics, 2014Co-Authors: Miles J Padgett, Filippo M Miatto, Martin P J Lavery, Anton Zeilinger, Robert W BoydAbstract:There is recent interest in the use of light Beams carrying orbital angular momentum (OAM) for creating multiple channels within free-space optical communication systems. One limiting issue is that, for a given Beam size at the transmitter, the Beam divergence angle increases with increasing OAM, thus requiring a larger aperture at the receiving optical system if the efficiency of detection is to be maintained. Confusion exists as to whether this divergence scales linarly with, or with the square root of, the Beam's OAM. We clarify how both these scaling laws are valid, depending upon whether it is the radius of the Gaussian Beam Waist or the rms intensity which is kept constant while varying the OAM.
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three dimensional optical confinement of micron sized metal particles and the decoupling of the spin and orbital angular momentum within an optical spanner
Optics Communications, 2000Co-Authors: Anna T Oneil, Miles J PadgettAbstract:We report a new mechanism for trapping metallic particles in inverted optical tweezers. The particles are loosely confined, in three dimensions, to an annular region just below the Beam Waist where gravity is counterbalanced by the scattering force. When using a Laguerre-Gaussian mode the trapping efficiency is improved and additionally we are able to observe an off-axis rotation of the particles around the Beam circumference which is induced by the orbital angular momentum of the Beam. Since there is no mechanism by which the spin angular momentum can contribute to the scattering force the spin and orbital angular momentum terms are decoupled and therefore the polarisation state does not influence the motion of the particles.
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second harmonic generation and the conservation of orbital angular momentum with high order laguerre gaussian modes
Physical Review A, 1997Co-Authors: Johannes Courtial, Kishan Dholakia, L Allen, Miles J PadgettAbstract:Laguerre-Gaussian modes of various order are frequency doubled. The azimuthal phase structure of the second-harmonic light is measured directly by interfering the Beam with its mirror image. We show that the orbital angular momentum per photon is doubled, so conserving the orbital angular momentum in the light Beam. The frequency-doubled output Beam is shown to have a Gegenbauer-Gaussian amplitude distribution at the Beam Waist. The Beam can be described as a summation of Laguerre-Gaussian modes that interfere so that it changes form with propagation, but the distribution at the Beam Waist is reproduced in the far field.
Silvânia A. Carvalho - One of the best experts on this subject based on the ideXlab platform.
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Maximal breaking of symmetry at critical angles and a closed-form expression for angular deviations of the Snell law
Physical Review A, 2014Co-Authors: Manoel P. Araújo, Silvânia A. CarvalhoAbstract:A detailed analysis of the propagation of laser Gaussian Beams at critical angles shows under which conditions it is possible to maximize the breaking of symmetry in the angular distribution and for which values of the laser wavelength and Beam Waist it is possible to find an analytic formula for the maximal angular deviation from the optical path predicted by the Snell law. For Beam propagation through $N$ dielectric blocks and for a maximal breaking of symmetry, a closed expression for the Goos-H\"anchen shift is obtained. The multiple-peak phenomenon clearly represents additional evidence of the breaking of symmetry in the angular distribution of optical Beams. Finally, the laser wavelength and Beam-Waist conditions to produce focal effects in the outgoing Beam are also briefly discussed.
Adrian Alexandrescu - One of the best experts on this subject based on the ideXlab platform.
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mechanism of angular momentum exchange between molecules and laguerre gaussian Beams
Physical Review Letters, 2006Co-Authors: Adrian Alexandrescu, Dan Cojoc, Enzo Di FabrizioAbstract:We derive the interaction Hamiltonian between a diatomic molecule and a Laguerre-Gaussian Beam under the assumption of a small spread of the center of mass wave function of the molecule in comparison with the Beam Waist. Considering the dynamical variables of the center of mass, vibrational, rotational, and electronic motion, we show that, within the electronic dipole approximation, the orbital angular momentum of the field couples with the rotational and electronic motion. The changes in the transition probabilities and selection rules induced by the field orbital angular momentum and the applicability of the derived interaction mechanisms for polyatomic molecules are discussed.
Isabelle Riou - One of the best experts on this subject based on the ideXlab platform.
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a marginally stable optical resonator for enhanced atom interferometry
Journal of Physics B, 2017Co-Authors: Isabelle Riou, Nicolas Mielec, Andrea Bertoldi, Benjamin Canuel, Arnaud Landragin, G Lefevre, Marco Prevedelli, Philippe Bouyer, R. GeigerAbstract:We propose a marginally stable optical resonator suitable for atom interferometry. The resonator geometry is based on two flat mirrors at the focal planes of a lens that produces the large Beam Waist required to coherently manipulate cold atomic ensembles. Optical gains of about 100 are achievable using optics with part-per-thousand losses. The resulting power build-up will allow for enhanced coherent manipulation of the atomic wavepackets such as large separation Beamsplitters. We study the effect of longitudinal misalignments and assess the robustness of the resonator in terms of intensity and phase profiles of the intra-cavity field. We also study how to implement atom interferometry based on Large Momentum Transfer Bragg diffraction in such a cavity.