Guidelines for Designing Surface Ion Traps Using the Boundary Element Method

Abstract

Ion traps can provide both physical implementation of quantum information processing and direct observation of quantum systems. Recently, surface ion traps have been developed using microfabrication technologies and are considered to be a promising platform for scalable quantum devices. This paper presents detailed guidelines for designing the electrodes of surface ion traps. First, we define and explain the key specifications including trap depth, q-parameter, secular frequency, and ion height. Then, we present a numerical-simulation-based design procedure, which involves determining the basic assumptions, determining the shape and size of the chip, designing the dimensions of the radio frequency (RF) electrode, and analyzing the direct current (DC) control voltages. As an example of this design procedure, we present a case study with tutorial-like explanations. The proposed design procedure can provide a practical guideline for designing the electrodes of surface ion traps.

A New Measurement Method for High Voltages Applied to an Ion Trap Generated by an RF Resonator

“…A typical chamber for an ion trap experiment is composed of pumps for ultra-high vacuum, viewports, feedthroughs for DC and RF voltages, and an ion trap structure [ 33 , 34 ]. We use a Paul trap in the shape of a surface ion trap [ 35 , 36 ] and mount it in a vacuum chamber with a pressure of approximately 2 × 10 −11 Torr at room temperature. A high RF voltage amplified by a helical resonator is applied to the ion trap through the RF feedthrough.…”

“…Then we find by adding all the electric fields calculated for all the RF electrodes and scaling it by the RF voltage amplitude ( ), where represents the position vector. Finally, the pseudopotential is found by [ 35 ] where is the charge of the ion, is the mass of the ion, and is the radio frequency of the voltage applied to the RF electrodes. The static potential can be calculated by linear combination of the other electric fields generated by all DC electrodes, and the total potential can be obtained by adding the pseudopotential ( ) and the static potential.…”

“…Then we find E RF (r) by adding all the electric fields calculated for all the RF electrodes and scaling it by the RF voltage amplitude (V T ), where r represents the position vector. Finally, the pseudopotential is found by [35]…”

Experimental Methods for Trapping Ions Using Microfabricated Surface Ion Traps

“…NOTE: After step 2.2.12, it can be assumed that the center of the beam is right on the chip surface. From the numerical simulation of the trap potential 29 , find the expected height of the ion trapping position from the chip surface. Move the 369.5 nm beam away from the chip surface by the expected height using the micrometer of the lens translation stage.Move the imaging lens and the EMCCD back by the same distance.…”

“…The methodology for designing a DC voltage set is included in the Supplementary Document . In addition, more details for designing the essential geometric parameters of surface ion-trap chips can be found in 27 28 29 30 31 .…”