Honors Program


Date of this Version

Spring 3-2020

Document Type



Fitzgarrald, R. 2020. Spiral Wavefronts in Rubidium Fluorescence: Testing the Spatial Resolution Limits of CCD Cameras. Undergraduate Honors Thesis. University of Nebraska-Lincoln.


Copyright Rebecca Fitzgarrald 2020.


The goal of the project was to observe a spiral wavefront in the fluorescent light from rubidium atoms, an idea that has been described in theory but not shown experimentally. When unpolarized light with a specific wavelength passes through rubidium atoms, it creates a spherical wavefront that is uniform in all directions. When the light becomes circularly polarized, this wavefront should become a spiral instead. We wanted to observe this shift by using a grating to create a diffraction pattern which should shift up or down depending on the helicity of the incoming light. We created a diffraction pattern with the fluorescence, but we needed to extensively test the camera's spatial resolution to see if it could detect the expected motion on the order of nanometers. After various forms of data analysis and testing two cameras, we believe we are being limited by systematic error that currently prohibits us from seeing such small motion. This error can be reduced by eliminating sources of shaking in the physical setup.