Experimental Realization of Superabsorption by Phase-Correlated Atoms in a Cavity

Experimental realization of superabsorption by using a time-reversed process of coherent superradiance is presented. Phase-correlated atoms in the same superposition state were prepared by using a nanohole array atomic beam aperture placed in front of a high-Q cavity. The time reversal was then achieved by preparing the phase of the superposition state of atoms opposite to that of the atoms which would generate the coherent superradiance with its phase the same as that of an input field. The intracavity field was depleted by superabsorption much faster than by the ordinary ground-state absorption. We experimentally observed that the maximum number of photons completely absorbed for a given time interval was proportional to N2 in contrast to the ordinary absorption proportional to N, the number of atoms in the cavity.