Transmission spectroscopy of a single atom in the presence of tensor light shifts

We investigate the interplay between Zeeman and light shifts in the transmission spectrum of an optically trapped, spin-polarized Rubidium atom. The spectral shape of the transmission changes from multiple, broad resonances to a single, narrow Lorentzian with a high resonant extinction value when we increase the magnetic field strength and lower the depth of the dipole trap. We present an experimental configuration well-suited for quantum information applications in that it enables not only efficient light-atom coupling but also a long coherence time between ground state hyperfine levels.