Dark-state optical potential barriers with nanoscale spacing

Abstract

Optical potentials have been a versatile tool for the study of atomic motions and many-body interactions in cold atoms. Recently, optical subwavelength single barriers were proposed to enhance the atomic interaction energy scale, which is based on non-adiabatic corrections to Born-Oppenheimer potentials. Here we present a study for creating a new landscape of non-adiabatic potentials-multiple barriers with subwavelength spacing at tens of nanometers. To realize these potentials, spatially rapid-varying dark states of atomic Λ-configurations are formed by controlling the spatial intensities of the driving lasers. As an application, we show that bound states of two and three atoms via magnetic dipolar interactions with weak magnetic moments can be realized in our scheme. Imperfections and experimental realizations of the multiple barriers are also discussed.

Optical lattice with spin-dependent sub-wavelength barriers

“…The characteristic distances over which optical lattice potentials change are limited by diffraction and thus cannot be smaller than half of the optical wavelength λ. Yet the diffraction limit does not necessarily apply to optical lattices [5][6][7][8][9] or other sub-wavelength structures [10][11][12][13][14][15][16][17] relying on coherent coupling between atomic internal states.…”

“…It was demonstrated theoretically [5,6,8,9,18] and experimentally [19,20] that a periodic array of sub-wavelength barriers can be formed for atoms populating a long lived dark state of the Λ-type atom-light coupling scheme. These barriers appear in regions of steep change in the dark state due to the geometric scalar (Born-Huang) potential [18,21,22].…”

Dipolar physics: A review of experiments with magnetic quantum gases

“…Such regimes are on the edge of the experimental possibilities to-date. To mitigate these constraints, interesting approaches consist in designing optical lattices with small (sub-wavelength) spacings, thus increasing the NNI coefficient [733][734][735][736][737][738][739]. Finally, preparation and detection schemes at the singleatom level [630,740,741] are a direction of broad interest which would ease the observation of exotic phases as well as many others effects of interests, e.g.…”

Soliton Interferometry with Very Narrow Barriers Obtained from Spatially Dependent Dressed States

“…These processes have recently been investigated experimentally [19]; in a typical setup, focused blue-detuned laser beams realize barriers on the micron scale, comparable to a typical soliton width [19,20]. A known method to produce subwavelength features is via rapid change over a small region of the amplitude of one of two near-resonant laser fields in an atomic Λ configuration, which can be understood in terms of effective potentials experienced by spatially dependent dressed states [21][22][23][24][25][26][27][28][29]. We propose a technique exploiting these properties to create a single narrow barrier for soliton interferometry within a quasi-one-dimensional (quasi-1D) BEC.…”