Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/122000
Title: MANIPULATION AND DETECTION OF ATOMS USING PLASMON-ENHANCED EVANESCENT WAVES OVER DIELECTRIC WAVEGUIDES
Authors: YIK JINEN JOHNATHAN
Keywords: evanescent waves, plasmons, waveguides, fluorescence, dipole trapping, atom detection
Issue Date: 10-Oct-2014
Citation: YIK JINEN JOHNATHAN (2014-10-10). MANIPULATION AND DETECTION OF ATOMS USING PLASMON-ENHANCED EVANESCENT WAVES OVER DIELECTRIC WAVEGUIDES. ScholarBank@NUS Repository.
Abstract: Atom chip devices confine atoms by using the superposition of magnetic fields due to a current along with a uniform external field, generating a linear magnetic potential well along the line of the current. These devices are used in atomic physics experiments due to their ability to produce extremely tight confinements. In particular, the high phase-space densities made available by tight confinements allow rapid creation of Bose-Einstein condensates, while the strength of the transverse confinement compared to the weak axial confinement allows 1-dimensional states of matter to be created and studied. To achieve such tight confinements, atoms must be trapped very close to the chip surface. However, detection of atoms is difficult at small separations from the surface. Additionally, irregularities in the current-carrying wires produce corrugations in the trapping potential, causing fragmentation of trapped atoms, as well as undesired excitations out of the ground state. In this thesis, the integration of optical waveguides on the surface of atom chips is proposed, in order to address the previously-mentioned problems with atom confinement near the chip surface. Using evanescent waves enhanced by metal wires emplaced on the waveguide surface, atoms may be detected via fluorescence imaging, or trapped using induced dipole potentials from oppositely detuned wavelengths of light coupled through the guide. We report the results of finite-difference time-domain simulations of metal wires embedded on waveguide surfaces. Enhanced evanescent waves due to surface plasmons excited within the wires are calculated. The use of these waves to carry out fluorescent imaging of atoms over the chip surface is examined. Fluorescent rates are calculated for the 5s-5p transition in rubidium, as well as the two-photon transition between the 5s and 4d states. In addition to this, we examine the dipole forces acting on atoms above the wires, in particular, of forces acting in opposite directions due to two oppositely-detuned wavelengths coupled down the same guide. By tuning the relative powers of the two modes, it is found possible to achieve a long, narrow trapping potential over the waveguide. Finally, we examine the use of such a trap for creating and manipulating 1-dimensional states of matter, in particular, the creation of 1-dimensional strings of impenetrable atoms, also known as Tonks-Girardeau gases, and compare the characteristics of such a gas created in the evanescent-wave dipole trap to previous experiments making use of crossed-beam optical lattice potentials.
URI: http://scholarbank.nus.edu.sg/handle/10635/122000
Appears in Collections:Ph.D Theses (Open)

Show full item record
Files in This Item:
File Description SizeFormatAccess SettingsVersion 
YikJY.pdf10.01 MBAdobe PDF

OPEN

NoneView/Download

Page view(s)

52
checked on Nov 2, 2018

Download(s)

49
checked on Nov 2, 2018

Google ScholarTM

Check


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.