Two-color MOT

[henryfpassagem]

Is it possible to run a two-color MOT simulation? I am interested in simulated the experiments that accomplished two-photon cooling of Mg and Cs. Please, check the references below

https://journals.aps.org/pra/abstract/10.1103/PhysRevA.77.021402
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.103.173003

[ElliotB256]

Short answer is: No, not currently.

AtomECS currently performs a rate equation approximation of a two level system (with minor caveat that different sigma_-, sigma_+, pi transitions between different zeeman states can be driven and treated separately). AtomECS could probably be adapted to consider other cases, but I won't have time to do that for the foreseeable future.

The two level code works by calculating the rate coefficient between ground and excited, for each laser beam, and then using the summed rates to determine the final populations in ground/excited states (so as to model power saturation properly for multiple beams). If you can model the system as coupled rate equations, with e.g. three levels (|g>, |e>, |e'>) driven by two transitions (Gamma_eg, Gamma_e'e), then you could probably adapt the existing two level code without too much extra work. You'd sum the rate coefficients for each laser, between g<->e and e<->e', solve for the populations in each state, and then use that to determine scattering rates on each transition. You'd be able to reuse all the existing code for integration, magnetic fields, simulation regions, output, laser intensities.

I hope this helps, let me know if anything is unclear. Happy to chat further!