All-Optical Matter-Wave Lens using Time-Averaged Potentials

Abstract

The stability of matter-wave sensors benefits from interrogating large-particle-number atomic ensembles at high cycle rates. The use of quantum-degenerate gases with their low effective temperatures allows constraining systematic errors towards highest accuracy, but their production by evaporative cooling is costly with regard to both atom number and cycle rate. In this work, we report on the creation of cold matter-waves using a crossed optical dipole trap and shaping it by means of an all-optical matter-wave lens. We demonstrate the trade off between residual kinetic energy and atom number by short-cutting evaporative cooling and estimate the corresponding performance gain in matter-wave sensors. Our method is implemented using time-averaged optical potentials and hence easily applicable in optical dipole trapping setups.

Asymmetric tunneling of Bose–Einstein condensates

“…argument does not apply to the case of trapping potentials because the condition of asymptotically vanishing potential is violated. Because trapping potentials are better suited for experimentally studying asymmetric tunneling of a BEC by utilizing painted potentials [43][44][45], we ought first to confirm the symmetry of tunneling for the Schrödinger equation under trapped conditions before contrasting the results with the GPE.…”

“…To continue our investigation, we have chosen parameters such that our trapping asymmetric potential (see equation (24)) may be entirely created by a series of fixed-width Gaussians of varying intensity, which could be realized by a time-averaged experimental technique [43][44][45]. To best match future experimental parameters, the potential is comprised of Gaussians corresponding to a waist size of ≈17 µm (figure 13): Ṽ(ξ) =400 − 285 e −(ξ+45) 2 /144.5 + e −(ξ−45) 2 /144.5 + e −(ξ+30) 2 /144.5 + e −(ξ−30) 2 /144.5 − 242.25 e −(ξ+15) 2 /144.5 + e −(ξ−15) 2 /144.5…”

Rapid generation of all-optical $^{39}$K Bose-Einstein condensates using a low-field Feshbach resonance

“…1 b)) and a maximum power of 8 W in the primary and 6 W in the secondary beam. By modulating the center-position of the laser beams we generate time-averaged potentials in the horizontal plane using an acousto-optical modulator [24,25,33]. With this we can reach trap depths from U 0 = 130 nK to 530 µK, corresponding to trapping frequencies of ω/2π = {4; 6; 50} Hz to {1.3; 1.9; 2.2} kHz in {x; y; z}-direction.…”

“…With the ability to focus optical dipole trap beams into the center of the experimental apparatus, generally this leaves a larger clear aperture for optical access as compared to atom chip solutions [20,21]. Moreover, recent studies have shown a variety of tools to counteract the typical scaling laws when evaporatively cooling in optical traps [22], e.g., by movable lens systems [23] or dynamically shaped time-averaged potentials [24,25]. Finally, while trapping any substate irrespective of whether high or low magnetic field seeking, optical traps offer ideal conditions for studying and utilizing Feshbach resonances with the external magnetic field as a free parameter [26].…”

Asymmetric Tunneling of Bose-Einstein Condensates

“…with the barrier once. The asymmetric barrier is formed by a series of fixed width Gaussians of varying intensity and could be realized by a time-averaged technique as experimentally done in references [36][37][38]: Ṽ (ξ) =45e −(ξ+15) 2 /144.5 + 31.5e −ξ 2 /144.5 + 13.5e −(ξ−15) 2 /144.5 .…”