Realization of a deeply subwavelength adiabatic optical lattice

We propose and describe our realization of a deeply subwavelength optical lattice for ultracold neutral atoms using resonantly Raman-coupled internal degrees of freedom. Although counterpropagating lasers with wavelength provided two-photon Raman coupling, the resultant lattice period was /2 , an -fold reduction as compared to the conventional /2 lattice period. We experimentally demonstrated this lattice built from the three = 1 Zeeman states of a Rb Bose-Einstein condensate, and generated a lattice with a /6 = 132 nm period from = 790 nm lasers. Lastly, we show that adding an additional rf-coupling field converts this lattice into a superlattice with wells uniformly spaced within the original /2 unit cell.