journal club 23rd march 2011 - windows
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8/2/2019 Journal Club 23rd March 2011 - Windows
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OU :: Department of Physics &
Astronomy :: Journal Club
Alexander Baker23rd March 2011
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Propagation dynamics of optical
vortices .Journal of Optical Society of America B/Volume14th3054-3065 (Nov1997).
D. RozasDepartment of Physics, Worcester Polytechnic
Institute, Worcester, Massachusetts.C. T. LawDepartment of Electrical Engineering and
Computer Science, University of Wisconsin, Milwaukee.
G. A. Swartzlander, Jr. Department of Physics, Worcester
Polytechnic Institute, Worcester, Massachusetts.
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University College London
Department of Physics & Astronomy, Dr PhillipJones
Optical Tweezers Group
Summer project to investigate a numerical model for
the propagation of OVs in linear and non linearmediums.
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Contents
Section 1: Background & Introduction Section 2: Review of definitions
Section 3: Analytical descriptions of the propagation
dynamics
Section 4: Numerical and revised theoretical analysesfor special cases
Section 5: Conclusions
UCL Model, demonstration and findings
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Section 1: Background
Optical Vortex Light can be twisted like a corkscrew around its axis
of travel, light waves at the axis cancel each other out.
Projected ring of light.
Topological Charge.
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Section 1: Introduction
Dynamics similar to hydrodynamic vortexphenomena.
Develop intuitive understanding of OV motion.
Describe propagation dynamics of different types of
vortices. Applications in Optical Tweezers, Exoplanet
detection, Quantum Computing.
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Section 2: Definitions and Properties of
OVs.
Field of single
vortex with Ansatz
G_{bg} - Gaussianprofile.
Compare and
contrast two core
functions.
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Section 3 : Analytics Descriptions of
the propagation dynamics.
Scalar paraxial
propagation, linear
and nonlinear. Phase and intensity
gradient
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Section 3.1 : Gaussian beam dynamics.
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Phase increases 2pi
clockwise both cores.
No rotation found
around optical axis.
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Section 4: Numerical analyses
for special cases
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Split step or beam
propagation method.
Linear and non linear
terms.
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Section 5: Conclusions
Three factors that affect motion of optical vortices Amplitude gradient
Phase gradient
non linear factordepends on intensity gradient
Contrasting differences between r and tanh corefunctions.
Discuss 4 different cases
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Case 1: Linear vortexLinear propagation of a vortex placed in the centre of a
Gaussian beam.
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Diffraction ringing
may occur in near
field
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Case 2: Nonzero background gradientDisplaced vortex from the centre of the beam to location
with non zero background gradient
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Single tanh vortex
expected to move in
straight line
propagation.
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Case 3: Second vortexIntroduce a second vortex, trajectory affected by Gaussian
field and field of second vortex.
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R vortex no
rotation.
Pair of tanh
vortices significant
rotation
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Case 3: Second vortexIntroduce a second vortex, trajectory affected by Gaussian
field and field of second vortex.
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Case 4: Nonlinear mediaIntroduce self-defocusing non linear medium.
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Section 5: Conclusions
Three factors that affect motion of optical vortices Amplitude gradient
Phase gradient
non linear factordepends on intensity gradient
Contrasting differences between r and tanh corefunctions.
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UCL Model & Findings ::
animations
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OU :: Department of Physics &
Astronomy :: Journal Club
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Appendix A : Geometry.
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Ginzburg and
Pitaevskii.
Scalar paraxial
propagation, linear
and nonlinear.
Hydrodynamic
paradigms describe
EM phenomena
Phase and intensity
gradient.
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