Doppler-free approach to optical pumping dynamics in the $6S_{1/2}-   5D_{5/2}$ electric quadrupole transition of Cesium vapor
  The $6S_{1/2}-5D_{5/2}$ electric quadrupole transition is investigated in Cesium vapor at room temperature via nonlinear Doppler-free 6P-6S-5D three-level spectroscopy. Frequency-resolved studies of individual E2 hyperfine lines allow one to analyze optical pumping dynamics, polarization selection rules and line intensities. It opens the way to studies of transfer of light orbital angular momentum to atoms, and the influence of metamaterials on E2 line spectra. 
Eng Aik Chan, Syed Abdullah Aljunid, Nikolay I. Zheludev, David   Wilkowski, Martial Ducloy
physics.atom-ph physics.optics