CAVITY QED WITH HIGH-Q WHISPERING GALLERY MODES

We report measurements of cavity-QED effects for the radiative coupling of atoms in a dilute vapor to the external evanescent field of a whispering-gallery mode (WGM) in a fused silica microsphere. The high Q (5 x 10^(7)), small mode volume (10^(-8) cm^(3)), and unusual symmetry of the microcavity evanescent field enable velocity-selective interactions between fields with photon number of order unity in the WGM and (N) over bar(T) similar to 1 atoms in the surrounding vapor.