Thesis

Holographically generated light potentials for cold-atom experiments

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Awarding institution
  • University of Strathclyde
Date of award
  • 2025
Thesis identifier
  • T17235
Person Identifier (Local)
  • 202063334
Qualification Level
Qualification Name
Abstract
  • This thesis presents computational and experimental techniques to generate light potentials of arbitrary shapes holographically using a phase-modulating liquid-crystal spatial light modulator (SLM) for experiments with ultracold atoms. Many quantumsimulation and quantum-computing experiments using ultracold atoms have benefited from programmable local control on a microscopic scale. Inhomogeneities in the light potentials used in these experiments must be reduced to mitigate dephasing effects or heating of the atoms. Further, in applications where laser power is limited, a high efficiency is desirable. Here, I demonstrate the generation of holographic light potentials with a root-mean-squared (RMS) error below 1% and a measured efficiency of up to ∼ 40%. I show that in a Fourier imaging setup, for light potentials which occupy a significant fraction of the addressable area in the image plane, a parasitic effect on the SLM known as pixel crosstalk or fringing field effect limits the accuracy of the light potential. By modelling this pixel crosstalk and by compensating for its effects, the error in the light potential is reduced by a factor of ∼ 5. A gradient-based optimisation algorithm is employed to calculate the SLM phase pattern for the desired light potential. To reduce experimental errors, we measure the wavefront of the incident laser beam to within λ/120 and employ an iterative camera feedback algorithm. To downscale the light potentials to a microscopic scale, a high-NA microscope objective is used. Finally, a fast method to calibrate the experimental setup is demonstrated, reducing the runtime from ∼ 3 hours to ∼ 5 minutes, maintaining an RMS error of below 1% in the resulting light potentials.
Advisor / supervisor
  • Pritchard, Jonathan D.
  • Kuhr, Stefan
  • La Rooij, Arthur
Resource Type
DOI
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file details PDF of thesis T17235 2025-03-26 Public Download