Surface trap with dc-tunable ion-electrode distance

Abstract

We describe the design, fabrication, and operation of a novel surface-electrode Paul trap that produces a radio-frequency-null along the axis perpendicular to the trap surface. This arrangement enables control of the vertical trapping potential and consequentially the ionelectrode distance via dc-electrodes only. We demonstrate confinement of single 40 Ca + ions at heights between 50 µm and 300 µm above planar copper-coated aluminium electrodes. We investigate micromotion in the vertical direction and show cooling of both the planar and vertical motional modes into the ground state. This trap architecture provides a platform for precision electric-field noise detection, trapping of vertical ion strings without excess micromotion, and may have applications for scalable quantum computers with surface ion traps.

Distance scaling and polarization of electric-field noise in a surface ion trap

“…In our experiment, we investigate the electric-field noise as a function of ion-surface distance for a single 40 Ca + ion trapped in a unique surface Paul trap with a simple planar geometry. Our room-temperature four-RFelectrode trap enables tuning of the ion-surface distance at a fixed planar position using DC voltages [15], and we find that the magnitude of noise for this trap is comparable to the best untreated traps. We measure electricfield noise in both the normal and planar directions with respect to the surface and extract a distance scaling exponent of β ≈ 2.6 for ion-surface distances in the range of 50 − 300 µm, significantly departing from the previous measurements discussed above.…”

“…25 MHz. The range of ion-electrode distances accessible with the trap is limited by the high RF voltages needed when trapping close to and far away from the surface [15]. We also find that for measure- ments of the normal mode, care must be taken to reduce back-reflections of the normal 729 nm beam from the trap surface, which cause significant intensity fluctuations at the ion position, leading to unreliable measurements especially for small distances from the trap surface.…”

“…The trap is operated with an out-of-phase RF drive such that the two diagonal pairs of RF electrodes (RF 1,4 and RF 2,3 ) are driven with the same amplitude, but opposite phase. This generates a radio-frequency-null along the axis normal to the trap surface [15]. Thus, the trapping potential in this direction is fully controlled with DC electrodes (1 to 9), allowing for continuous variation of the ion-surface distance without introducing excess micromotion.…”

Segmented ion-trap fabrication using high precision stacked wafers

“…In recent years several experiments and applications have demonstrated the strength of this technology. Applications include laser written optical waveguides [31][32][33][34][35], creation of high aspect ratio micro-fluidic channels [30,31,36], flextures [36], MEMS [37] and ion traps [38][39][40]. We are currently aware of two companies offering a customizable femtosecond laser machining service: [31], which is known as Laser Affected Zone (LAZ).…”

Surface-Electrode Ion Trap With Ground Structures for Minimizing the Dielectric Loss in the Si Substrate

“…These traps are designed with multiple and irregular DC electrodes and fabricated with multilayer metal structures to facilitate precise ion control and shuttling with enhanced trapping performance. Apart from these, new types of ion traps such as microwavecontrolled electrode trap [10] and surface trap with tunable ion distance [11] have been demonstrated by other research groups. Due to the increasing complexity and diversity requirement imposed on the surface trap design, the consideration to incorporate the trap fabrication into a more foundry compatible, large-volume and fast turn-over time production to prove the design concept becomes imperative.…”