Simulation of EOM-based frequency-chirped laser slowing of MgF radicals

Abstract

Here we propose a scheme to slow MgF molecules by using EOM-based frequency-chirped radiation pressure slowing. The scheme well addresses the need for a rapid chirp rate while light molecules are being laser slowed, whose scattering rate and recoil velocity are large. Two EOMs are used to compensate the rapidly changing Doppler shifts arised from the movement of molecules, and to cover the hyperfine energy structure of MgF, respectively. Based the scattering rate maps calculated from an optical Bloch equation model, individual molecule trajectories are simulated by using a semi-classical three-dimensional Monte Carlo approach. We show how the modulation configuration of EOM and the magnetic field influence the slowing results. The study shows that a cryogenic buffer gas-cooled MgF beam source is possible to be slowed down with a number of ～ 1.4 × 10⁶–10⁷, and the final forward speed peaks at ～ 10 m/s near the capture velocity of a molecular MOT.

Graphical abstract

Keywords

laser cooling of molecule / MgF molecule / laser slowing / dark state / type-II transition

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