A new Manifestation of Atomic Parity Violation in Cesium: a Chiral   Optical Gain induced by linearly polarized 6S-7S Excitation
  We have detected, by using stimulated emission, an Atomic Parity Violation (APV) in the form of a chiral optical gain of a cesium vapor on the 7S - 6P$_{3/2}$ transition,consecutive to linearly polarized 6S-7S excitation. We demonstrate the validity of this detection method of APV, by presenting a 9% accurate measurement of expected sign and magnitude. We underline several advantages of this entirely new approach in which the cylindrical symmetry of the set-up can be fully exploited. Future measurements at the percent level will provide an important cross-check of an existing more precise result obtained by a different method. 
J. Gu\'ena, D. Chauvat, Ph. Jacquier, E. Jahier, M. Lintz, A.V.   Papoyan, S. Sanguinetti, D. Sarkisyan, A. Wasan, M.A. Bouchiat