3D-printed micro ion trap technology for quantum information applications

Trapped-ion applications, such as in quantum information processing¹, precision measurements^2-5, optical clocks⁶ and mass spectrometry⁷, rely on specialized high-performance ion traps. The last three of these applications typically use traditional machining to customize macroscopic 3D Paul traps⁸, whereas quantum information processing experiments usually rely on photolithographic techniques to miniaturize the traps and meet scalability requirements^9,10. Using photolithography, however, it is challenging to fabricate the complex 3D electrode structures required for optimal confinement. Here we demonstrate a high-resolution 3D printing technology based on two-photon polymerization (2PP)¹¹ that is capable of fabricating large arrays of high-performance miniaturized 3D traps. We show that 3D-printed ion traps combine the advantages, such as strong radial confinement, of traditionally machined 3D traps with on-chip miniaturization. We trap calcium ions in 3D-printed ion traps with radial trap frequencies ranging from 2 MHz to 24 MHz. The tight confinement eases ion cooling requirements and allows us to implement high-quality Rabi oscillations with Doppler cooling only. Also, we demonstrate a two-qubit gate with a Bell-state fidelity of 0.978 ± 0.012. With 3D printing technology, the design freedom is greatly expanded without sacrificing scalability and precision, so that ion trap geometries can be optimized for higher performance and better functionality.