Coherent bichromatic spectroscopy of Rb vapor with a femtosecond laser

We experimentally studied the narrow resonances of coherent population trapping (CPT) in a rubidium vapor cell with the help of a phase‐coherent bichromatic light source based on a mode‐locked femtosecond laser. We investigated the dependence of the contrast and the width of CPT resonance on the light power, as well as the sensitivity of the shape of the resonance to a magnetic field. Prospects of using the novel bichromatic source for phase‐coherent Raman spectroscopy of CPT resonances in atomic systems with a large energy separation of the lower levels are discussed. Copyright © 2006 John Wiley & Sons, Ltd.