Two- And Three-Photon Resonances in Rydberg Atoms for Localized Measurement

In this project, we investigated methods to make localized measurement of electric field with Rydberg electromagnetically induced transparency (EIT). Under EIT, opaque medium becomes transparent to near resonance optical fields. It is usually implemented with two laser beams completely overlapped, which can probe atomic response to external electric field precisely but lack spatial resolution. We proposed three different methods to obtain spatial information about electric field distribution. First we studied the modifications of Rydberg EIT resonances in non-collinear geometry, when two laser fields cross at a non-zero angle. We compared resonances in crossed-beam with collinear geometry and observed strong broadening and weakening of EIT resonance even when crossing angle is small. Our results show the tradeoff between spectroscopic sensitivity and spatial resolution of crossed-beam EIT. We also explored fluorescence imaging as an alternative way of making spatially resolved measurement. Lastly, we observed Rydberg EIT resonance in three-photon excitation scheme and reported our progress toward implementing three-photon EIT to perform localized, Doppler-free measurement.