The first two chapters of the thesis are primarily a review of the work in the field. Chapter 1 focusses on optomechanics broadly and chapter 2 on levitated systems, which are of particular interest due to their thermal isolation from the surroundings. Chapters 3, 4 and 5 consist of my own research, much of which was presented in papers published in 2012* and 2013**. * Pender, G. A. T., Barker, P.F., Marquardt, F., Millen, J. and Monteiro, T. S. Phys. Rev. A 85 021802 (2012) ** Monteiro, T. S., Millen, J, Pender, G. A. T., Marquardt, F., Chang, D. and Barker, P. F., New J. Phys. 15, 015001 (2013) Chapter 3 is primarily concerned with determining the conditions for trapping and cooling a dielectric sphere in an optical cavity, with two laser modes. It is found that, by using two symmetric cooling and trapping beams (as opposed to the one-field-trapping-one-field-cooling of Chang et. al.) we predict around twenty times greater level of cooling than previously predicted. Typical experimental parameters are presented in section 3.7. Chapter 4 deals with additional complications and considerations including: beads with a diameter which is a significant proportion of the diving wavelength, the effect of damping, heating and radiometric forces from the background gas, heating by black body radiation and other more realistic assumption. From this I am able to conclude that the dominant source of heating is the background gas and that, despite this heating, ground state cooling would still be possible at realistically low pressure (of less than 10-7 mbar). Chapter 5 discusses how we might observe quantum behaviour in this system. In this chapter I am able to determine that quantum behaviour is observable via a heterodyne detection which allows an asymmetry to be observed in the positional power spectrum of the bead (a classically impossible result).
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:747741 |
| Date | January 2018 |
| Creators | Pender, G. A. |
| Publisher | University College London (University of London) |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://discovery.ucl.ac.uk/10049699/ |
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