A coherent optical lattice with subwavelength structure


Sarthak Subhankar (JQI)
January 26, 2018
PSC 2136

*Snacks and drinks at 4 pm*

Coherent control of the position and motion of neutral atoms using the ac-Stark shift induced by light has been the workhorse in the field of quantum simulation. This approach, where the optically produced spatial potential is proportional to the light intensity, is fundamentally limited by the wave nature of the light and cannot produce spatial features with subwavelength resolution. In this talk, I will present an experiment where a 1D array of ultra-narrow barriers are created with width smaller than 1/50 the wavelength of the light. Instead of ac-Stark shift, this potential is based on the geometric potential atoms experience moving in a specially designed light field. Since this effect is both geometric and quantum in nature, it overcomes the diffraction limit of the light generating the potential. We study the band structure and dissipation of atoms in this lattice and compare our findings with theoretic predictions. The ability to coherently manipulate atoms on a subwavelength scale opens many exciting opportunities, including tunnel junctions for atomtronics applications, nearly perfect box-like atom traps, and stroboscopically generated lattices with subwavelength spacings.