Optical ferris wheel for ultracold atoms

Abstract

We propose a versatile optical ring lattice suitable for trapping cold and quantum degenerate atomic samples at discrete angular positions. We demonstrate the realisation of intensity patterns generated from Laguerre-Gauss ($\exp(i \ell\theta)$) modes with different $\ell$ indices. The ring lattice can have either intensity maxima or minima, suitable for trapping in red or blue detuned light, and it can be rotated by introducing a frequency shift between the Laguerre Gauss modes. The potential wells can be joined to form a uniform ring trap, making it ideal for studying persistent currents and the Mott insulator transition in a ring geometry.