High contrast measurements with a Bose-Einstein condensate atom interferometer

Rights statement
Awarding institution
  • University of Strathclyde
Date of award
  • 2016
Thesis identifier
  • T14411
Person Identifier (Local)
  • 201274859
Qualification Level
Qualification Name
Department, School or Faculty
  • Atom interferometry is a next-generation technique of precision measurement that can vastly outperform its optical analogue. These devices utilise the wave nature of atoms to make interferometric measurements of, for example, gravitational and magnetic fields, inertial effects, and the fine-structure constant. The main focus of this thesis is the creation of a general purpose atom interferometer in free space.We create a Bose-Einstein condensate of ~10⁵ ⁸⁷Rb atoms in a crossed-optical dipole trap. The atomic wave function is coherently manipulated using highly tuned pulses comprising off-resonant light that form our atom-optical elements. These atom optics are analogous to the beam splitters and mirrors in an optical interferometer. By controlling the timing and amplitude of the pulses we demonstrate the ability to excite specific momentum states with high efficiency. The tuned atom optics allows for the construction of an atom interferometer in free space. From this we can measure the recoil velocity of an ⁸⁷Rb atom and calculate the value of the fine structure constant. We also demonstrate the measurement of magnetic field gradients using atom interferometry. A second method of data readout is also demonstrated, known as contrast interferometry.This increases the rate at which information is obtained and decreases the measurement duration from a few hours to a few minutes.Within the vacuum chamber we also have a copper ring which form the basis of an AC coupled ring trap for atoms. The long term goal is to use this as a waveguide for atom interferometry and, whilst not the main focus of this thesis, we present some proof-of-principle type data demonstrating the ring trap. In addition we show the first Kapitza-Dirac splitting of a BEC within the waveguide which forms the first part of a guided atom interferometer.
Advisor / supervisor
  • Griffin, Paul
  • Riis, Erling
Resource Type
Managing organisation
  • Scottish Universities Physics Alliance