Proposal for high-precision atomic-parity-violation measurements by amplification of the asymmetry by stimulated emission in a transverse electric and magnetic field pump-probe experiment

Amplification by stimulated emission of radiation provides an interesting means for increasing the sensitivity of atomic-parity-violation (APV) measurements in a pump-probe configuration well adapted to the 6S-7S Cs transition. It takes advantage of the large number of atoms excited along the path of the pump beam. In the longitudinal electric field configuration currently exploited in our ongoing APV measurement, this number is limited only by the total voltage sustainable by the Cs vapor. To overcome this limit we consider, both theoretically and experimentally, the possibility of performing the measurements in a transverse electric field configuration requiring a much lower voltage. We discuss the necessarily different nature of the observable and the magnetoelectric optical effects that come into play. These condition modifications of the experimental configuration with, in particular, the application of a transverse magnetic field. We suggest the possibility of rotating the transverse direction of the fields so as to suppress systematic effects. With a long interaction length a precision reaching 0.1% in a quantum-noise-limited measurement can be expected, limited only by the necessity of operating below the threshold of spontaneous superradiant emission of the excited medium. Were we to approach this limit, however, we could greatly amplify the asymmetry using triggered superradiance.