Nanometer-scale optical traps using atomic state localization

Abstract

We suggest a scheme where a laser beam forms an optical trap with a spatial size that is much smaller than the wavelength of light. The key idea is to combine a far-off-resonant dipole trap with a scheme that localizes an atomic excitation.

Subwavelength-width optical tunnel junctions for ultracold atoms

“…The use of athree-level system to generate an optical potential in place of the typical two-level system offers more flexibility, because dark resonances [10] allow one to overcome the diffraction limit [11–21]. In this paper, building on previous studies of subwavelength-scale forces [22], atom localization [11–21,23–43], and non-dark-state-based techniques for building subwavelength potentials in the far field [44–55], we use the geometric scalar (Born-Huang) potential [56–58] experienced by spatially dependent dark states to create optical potential barriers with subwavelength widths. Our proposal has the advantage of not using lattice modulation, which could lead to heating, and of taking advantage of a feature—the geometric scalar potential—that naturally accompanies any subwavelength potential formed by spatially dependent dressed states.…”

Subwavelength Atom Localization

“…The CPT-based subwavelength atom localization idea (Agarwal & Kapale, 2006) has been taken further by others to theoretically propose schemes for subwavelength microscopy (Yavuz & Proite, 2007), subwavelength patterning of Bose-Einstein condensates (Mompart,Ahufinger, & Birkl, 2009), nanoscale trapping potentials for atoms (Yavuz, Proite, & Green, 2009), and two-dimensional localization by coupling the atom with two spatially dependent fields ( Jin, Sun, Niu, Jin, & Gong, 2009 (Shen, Xu, & Hu, 2007). Proite et al have carried out a proof-of-principle experiment of the CPT-based localization described above (Proite, Simmons, & Yavuz, 2011).…”

“…In another interesting proposal Yavuz et al have combined the ideas of atom localization with the idea of spatially varying energy shifts to propose theoretical possibility of nanometer scale optical traps for atoms (Yavuz et al, 2009). …”

Coherent optical nano-tweezers for ultra-cold atoms

“…In contrast, a three-level system with two coupling fields offers more flexibility and can generate a subwavelength optical potential even in the far-field: although the intensity profiles of both laser beams involved are diffraction-limited, the internal structure of the state can change in space on length scales much shorter than the wavelength λ of the lasers [9][10][11][12][13][14][15][16][17][18]. Such subwavelength internal-state structure can lead to subwavelength potentials either by creating spatially varying sensitivity to a standard AC Stark shift [19] or by inducing a conservative subwavelength geometric potential [20][21][22].…”

“…A trap based on the combination of AC Stark shift and subwavelength localization [9][10][11][12][13][14][15][16] within a three-level system was proposed in Ref. [19], but the geometric potentials arising from non-adiabatic corrections to the Born-Oppenheimer approximation [20,21] were not considered. In this Letter, we show that even with the repulsive non-adiabatic corrections, attractive subwavelength potentials are still possible.…”