Sculpting shadows. On the spatial structuring of fields & atoms: a tale of light and darkness

Clark, Thomas William (2016) Sculpting shadows. On the spatial structuring of fields & atoms: a tale of light and darkness. PhD thesis, University of Glasgow.

Abstract

Whether in art or physics, two dimensions are better than one.
And in this context, we consider the spatial shaping of optical
fields and atomic polarisations.

This work begins with a comprehensive review of how to
accurately and arbitrarily modulate transverse beam profiles
using six different methods. The methods are presented in the
context of a general complex input beam and the shaping and
measuring of the input beam with a single SLM is discussed and
demonstrated.
A simple setup is then considered that allows for the rapid
switching between arbitrary profiles, using only a single holo-
graphic component and an acousto-optical modulator (AOM). In
this setup, a switching speed of approximately 10 kHz is demon-
strated explicitly, limited by the current detection system, but
where speeds of up to 20 MHz are estimated to be possible.
The following discussion then concentrates on the spatial
structure of atoms, reviewing the conceptual tools needed to
measure and interpret an atomic cloud in the presence of a mag-
netic field from fundamental concerns, both in theory and in
practice: assuming a classical light field and a quantum atomic
system. The specific implementation of both a magneto-optical
trap and a holographically-shaped dynamic dark SpOT follows.

The crux of the work then concerns how polarisation-structured
light can be used to create spatial patterns of transparency (spa-
tial EIT) within an atomic cloud. Beginning with a review of EIT
in general, with particular focus on an F = 1 → F = 0 transition,
the spatial modulation of absorption, dispersion, polarisation
rotation and change in ellipticity is predicted for systems in the
presence of a transverse magnetic field. The depth of this mag-
netic field dependency is then explored in some detail, where the
relationship between observed patterns and applied magnetic
field suggests the possibility of a visual magnetometer. The final
section then considers how linearly polarised light and a q-plate
was used to demonstrate spatially dependent transparency in a
real atomic cloud.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: optics, atomic physics, eit, spatial eit, hologram generation, optical switching, magnetic sensing.
• Subjects: Q Science > QC Physics
• Colleges/Schools: College of Science and Engineering > School of Physics and Astronomy
• Supervisor's Name: Franke-Arnold, Dr. Sonja
• Date of Award: 2016
• Depositing User: Mr Thomas W Clark
• Unique ID: glathesis:2016-8029
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 04 Apr 2017 09:05
• Last Modified: 14 Jul 2017 16:09
• URI: https://theses.gla.ac.uk/id/eprint/8029