Suppression of single-cesium-atom heating in a microscopic optical dipole trap for demonstration of an 852-nm triggered single-photon source

摘要

We investigate single-cesium-atom heating owing to the momentum accumulation process induced by the resonant pulsed excitation in a microscopic optical dipole trap formed by a strongly focused 1064-nm laser beam. The heating depends on the trap frequency, which restricts the maximum repetition rate of the pulsed excitation. We experimentally verify the heating of a single atom and then demonstrate how to suppress it with an optimized pulsed excitation and cooling method. The typical trap lifetime of a single cesium atom is extended from 108 +/- 6 mu s to 2536 +/- 31 ms, and the corresponding number of excitations increases from similar to 108 to similar to 360 000. In applying this faster cooling method, we use the trapped single cesium atom as a triggered single-photon source at an excitation repetition rate of 10 MHz. The second-order intensity correlations of the emitted single photons are characterized by implementing a Hanbury Brown and Twiss setup, and a clear antibunching effect has been observed.