Manipulation Tools for Laser-Cooled Rubidium Atoms : Ultrathin Optical Fibres and Magnetic Diffraction Gratings / Michael J. Morrissey.
Date of Award
Doctor of Philosophy
Applied Physics & Instrumentation
Dr. Síle Nic Chormaic
Dr. Liam McDonnell
This thesis describes the construction and characterisation of a standard six-beam configuration magneto-optical trap (MOT) used to cool and trap neutral 85Rb atoms. This system is capable of producing a cloud of ~108 atoms whose average temperature is in the sub-Doppler range. The fabrication process for the production of subwavelength tapered optical nanofibres (TONFs) is also described, as well as their guiding properties. These have many proposed applications in the field of cold atoms. However, significant technical progress must be made before many of these applications can be realised. The objective of the research work was to combine the TONF with the cold atom setup to develop tapered optical nanofibres as a tool that can be used in cold atom experiments. This thesis presents a novel technique to measure the characteristics of a MOT by monitoring the spontaneous emission from the trapped atoms coupled into the guided mode of the TONF. This has allowed the measurement of cloud profile, loading times and decay times. This serves as a demonstration that TONFs can indeed play an important role in cold atom physics. The work presented here also describes a theoretical model for an atom diffraction grating based on oscillating magnetic fields produced by an array of current carrying wires.
Morrissey, Michael J., "Manipulation Tools for Laser-Cooled Rubidium Atoms : Ultrathin Optical Fibres and Magnetic Diffraction Gratings / Michael J. Morrissey." (2009). Theses [online].
Available at: https://sword.cit.ie/allthe/213