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

摘要

We investigate single cesium (Cs) atom heating owing to the momentumaccumulation process induced by the resonant pulsed excitation in a microscopicoptical dipole trap formed by a strongly focused 1064 nm laser beam. Theheating depends on the trap frequency which restricts the maximum repetitionrate of pulsed excitation. We experimentally verify the heating of a singleatom and then demonstrate how to suppress it with an optimized pulsedexcitation/cooling method. The typical trap lifetime of single Cs atom isextended from 108 +/- 6 us to 2536 +/- 31 ms, and the corresponding number ofexcitation increases from ~ 108 to ~ 360000. In applying this faster coolingmethod, we use the trapped single Cs atom as a triggered single-photon sourceat an excitation repetition rate of 10 MHz. The second-order intensitycorrelations of the emitted single photons are characterized by implementingHanbury Brown and Twiss setup, and clear anti-bunching effect has beenobserved.