Electron Beam Profiling Using Coherent Atomic Magnetometry

We demonstrate 2-dimensional imaging of a high-current electron beam using nonlinear optical polarization rotation in a sparse rubidium vapor. The magnetic field, produced by moving electrons, perturbs atomic spin states and causes rotation of a resonant linearly polarized optical field. By using atoms as local probes of magnetic field, we can extract the spatial information about the electron beam without perturbing it, and derive its current density distribution. We verify the obtained beam parameters, such as beam position and width, by comparing them with the beam images obtained using electron-induced rubidium fluorescence. Our method of charged particle beam profiling could be extended to the high-energy regime to act as a non-invasive diagnostic tool for nuclear particle accelerator experiments.