Decelerating a pulsed subsonic molecular beam by a quasi-cw optical lattice: 3D Monte-Carlo simulations

Abstract

We propose a practical scheme to realize the deceleration of a pulsed subsonic molecular beam by using a multistage optical Stark decelerator (i.e., a 1D quasi-cw, cavity-enhanced optical lattice), which is composed of two nearly counter-propagating, time-varying, red-detuned, light fields with an intensity of ∼108Wcm−2 in a folded ring resonator. The dependences of the molecular slowing effects on the synchronous phase angle, the deceleration-stage number and the initial central velocity of incident molecular beam as well as the cavity enhancement factor and its cavity length are investigated by the 3D Monte-Carlo method. Our study shows that the proposed decelerator cannot only be used to slow a pulsed subsonic beam from 240m/s to standstill, but also to obtain a ultracold molecular packet with a temperature of a few μK due to the bunching effect of our multistage optical Stark decelerator, and the corresponding fraction of cold molecules is 10−4–10−6, which strongly depends on the synchronous phase angle, the cavity enhancement factor and the initial central velocity of incident molecular beam, etc..