Coherent laser cooling with trains of ultrashort laser pulses

Abstract

We propose to extend coherent laser cooling from narrowband to broadband transitions by using trains of ultrashort broadband pulses. We analytically study two possible methods to reduce the momentum spread of a distribution by several units of photon momentum in a single spontaneous emission lifetime. We report on numerical simulations of one-dimensional laser cooling of a two-level system with realistic parameters. With this scheme, coherent laser cooling can in particular be implemented in the case of fast species with a short lifetime such as positronium.