Evanescent wave spectrosocpy in a heated Cs vapor

Abstract

We performed saturated absorption spectroscopy for the Cs D2 line using counter-propagating evanescent waves. The crossover resonance in the saturated absorption spectra by evanescent waves splitted into two peaks when the incident angles of the pump and the probe beams are different. As a result, atoms receive not the photon momentum, but the pseudomomentum from evanescent waves in a resonant interaction. We observed the broadened linewidth and the red-shift of each resonance line with the atomic vapor density. The broadening of linewidths might be caused by the atomic transit time.