Subwavelength optical dipole trap for neutral atoms using a microcapillary tube tip

Abstract

We propose a scheme for a state-insensitive optical dipole trap for single cesium atoms using a silica microcapillary tube tip. The end of microcapillary tube tip is flat. Simulations show that the trapping light beam output from microcapillary tube tip interferes and can form a subwavelength-trap with a full width at half-maximum of 0.67 μm. The trap is small enough to trap single atoms. The trap depth is more than 1 mK when the optical power of the trapping light guided by the microcapillary tube tip is only a few milliwatts. The effects of two imperfections, roughness of end surface and cutting angle, are estimated. The trapping depth for single atom trapping can be more than 1 mK when the average rms amplitude and average correlation length of tip surface roughness is smaller than 0.15 μm and the cutting angle is smaller than 16 degrees. Tip sizes on the order of microns are small enough to be combined within micro/nano structures for hybrid systems.

Tunable atom-trapping based on a plasmonic chiral metamaterial

“…Here, α is the reduced polarizability and its expression is taken from [49]. We considered eight transition wavelengths of 87 Rb, and the calculated value is α ≈ -7.87 × 10 e−38 F • m 2 at the trapping wavelength λ = 760 nm.…”

“…It can be easily seen that the trap depths are about 1.1 mK and 0.42 mK for RCP and LCP incidences, respectively, with input power P 0 = 1 mW. The full width at the halfmaxima (FWHMs) are both about 225 nm for RCP and LCP, which can be used to confine and trap a single atom [49]. Manipulation of a single atom can be used to verify basic physical laws and for accurate measurements of physical constants.…”

Blue-detuned optical atom trapping in a compact plasmonic structure

“…where the optical dipole potential U opt that a neutral atom with atomic state i and Zeeman level m i experiences in an electric field E is given by [5,7,36]…”

“…The dipole trap mainly uses the gradient light intensity formed by the focused light field to produce a dipole effect on a neutral atom. In the more used red-detuned traps, the atoms are trapped in the position with the strongest light intensity under attractive potential [6,7]. However, even in the case of a far-off resonance optical dipole trap (FORT) light, the atom will be subjected to large photon's Rayleigh and Raman scattering, resulting in obvious destruction of atomic coherence and heating effect [5].…”

“…In contrast, for the blue-detuned traps [9][10][11], the atoms are trapped in the weakest position under the exclusion potential; thus, the impact of the blue-detuned light is very small. But compared with the red-detuned traps, the construction of the blue-detuned traps is often more complex [4,[6][7][8][9][10][11]. Later on, the researchers proposed the use of an evanescent wave method to achieve atom trapping [12][13][14][15][16][17].…”