| An experiment has been designed, constructed, and tested to monitor the time evolution of a triply driven, three-level system in ground state atomic rubidium. Unlike lambda or ladder systems, this "delta" configuration (a closed loop of excitations) can exhibit time-asymmetric behavior. Because of this property, the three-level system is suitable for testing time reversal invariance.;We prepare the initial quantum mechanical state by optically pumping the rubidium atoms with a high power diode laser in an external cavity. Once the system has been prepared, three standing wave fields with mutually perpendicular polarization vectors are desired to drive the ground-state magnetic dipole transitions that constitute the delta system. These fields are generated using a novel triple resonator, which stores energy delivered from a dedicated microwave frequency chain. The composite device we have constructed facilitates precise control of the frequency, phase, amplitude, and polarization of the AC magnetic fields. CW probe lasers that we have built can continuously excite a small fraction of the coherently driven atoms into a high-lying optical state via a doppler-free, two photon transition. This state quickly decays via emission of a blue photon.;The intensity of the blue fluorescence signal can, in principle, exhibit time-directional sensitivity. This property is unique to systems comprised of a closed excitation loop. Such a signal can be analyzed to set limits on intrinsic T-violating effects in the rubidium atom or nucleus. |
