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Title: Studies of particle and atom manipulation using free space light beams and photonic crystal fibres
Author: Gherardi, David Mark
ISNI:       0000 0004 2718 0750
Awarding Body: University of St Andrews
Current Institution: University of St Andrews
Date of Award: 2009
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Light can exert optical forces on matter. In the macroscopic world these forces are minuscule, but on the microscopic or atomic scale, these forces are large enough to trap and manipulate particles. They may even be used to cool atoms to a fraction of a degree above absolute zero. This thesis details a number of experiments concerned with the optical manipulation of atoms and micron-size particles using free space light beams and photonic crystal fibres. Two atom guiding experiments are described. In the first experiment, a spatial light modulator is used to generate higher blue-detuned azimuthal Laguerre-Gaussian LG) beams, which are annular beams with a hollow core. These LG beams are then used to guide laser cooled rubidium-85 atoms within the dark core over a distance of 30 mm. The second atom guiding experiment involves attempting to guide laser cooled and thermal rubidium atoms through a hollow-core photonic crystal fibre using red-detuned light. Hollow-core photonic crystal fibres are fibres that are able to guide light with low attenuation within a hollow core. For this experiment a hot wire detection system was designed, along with a number of complex vacuum systems. The first dual-beam fibre trap for micron-size particles constructed using endlessly single-mode photonic crystal fibre (ESM-PCF) is described. The characteristics of dual-beam fibre traps are governed by the fibres used. As ESM-PCF has considerably different properties in comparison to conventional single- or multimode fibres, this dual beam ESM-PCF trap exhibits some novel characteristics. I show that the dual beam ESM-PCF trap can form trapping, repulsive and line potentials; an interference-free ‘white light’ trap; and a dual-wavelength optical conveyor belt.
Supervisor: Dholakia, Kishan Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Optical manipulation ; Photonic crystal fibre ; Atom guiding ; Large mode area fibre ; Spatial light modulator ; Laguerre- Gaussian ; Laser cooling ; Endlessly single-mode photonic crystal fibre ; White light ; Dual-beam fibre trap ; Optical conveyor belt ; PCF ; Supercontinuum ; ESM-PCF ; Optical fibre ; Hot-wire detector ; Hollow-core photonic crystal fibre ; Photonic bandgap fibre ; HC-PCF ; Rubidium