All-optical long-distance guide for cold molecules using a parallel hollow beam generated by a nonlinear ZnSe crystal

We propose a simple, controllable and highly efficient all-optical guide for a cw cold molecular beam in a blue-detuned parallel hollow beam over a long distance of ∼1 m. The hollow beam is generated by a beam shaper composed of a nonlinear ZnSe crystal. We demonstrate theoretically our optical molecular-beam guide and study its dynamic process by using Monte Carlo simulations. Our results show that the guiding efficiency can be easily controlled by adjusting the light intensity, and an ultracold collimated molecular beam with a transverse mean velocity of a few meters per second (the corresponding temperature is 13.67 mK) can be obtained. This guiding scheme has potential applications in molecule optics.