Surface-electrode point Paul trap

Abstract

We present a model as well as experimental results for a surface electrode radiofrequency Paul trap that has a circular electrode geometry well suited for trapping single ions and two-dimensional planar ion crystals. The trap design is compatible with microfabrication and offers a simple method by which the height of the trapped ions above the surface may be changed in situ. We demonstrate trapping of single 88 Sr + ions over an ion height range of 200-1000 µm for several hours under Doppler laser cooling and use these to characterize the trap, finding good agreement with our model.

Ideal multipole ion traps from planar ring electrodes

“…In the remainder of this section, we consider these two cases, as well as crystals consisting of small numbers of ions. We assume the crystallized ions have well-defined positions, despite the cylindrical symmetry of the trap, as was observed in [17]. These simple analyses shed light on some of the special properties of multipole traps, and especially SEMT's, which lend themselves easily to a simple description.…”

“…Understanding the relationship between r and y is important because Φ has no closed-form solution, except when r = 0 [17]. Let us see how we can use derivatives along y to null the potential to some order along r. We take successively the gradient and then the divergence of Eq.…”

“…As an example, the depth of the trap used in Ref. [17] is approximately 170 meV, which is typical for millimeter-scale surface-electrode ion traps. For Trap A with r 1 = 1 mm, we predict a depth of 50 eV when the trap is driven at 100 kHz with rf voltages of V 1 = 100 V,…”

“…This choice is based on the fact that a ring geometry allows one to trap ions in three dimensions using only rf (and no nonzero dc) potentials [17]. Our model trap ( Fig.…”

“…We assume that the distance between electrodes is zero and that the outer electrode is surrounded by a plane of infinite extent. Much work has been published on analytical solutions for the electric potential of surface-electrode ion traps [17][18][19][20][21];…”