arXiv:2502.09068 · Applied Physics Letters

Efficient quantum frequency conversion of ultra-violet single photons from a trapped ytterbium ion

Seungwoo Yu, Kyungmin Lee, Sumin Park, Kyunghye Kim, Junhong Goo, Jeonghyun Park, Taehyun Kim

Published Feb 24, 2025• 3 citations

Abstract

Ion trap system is a leading candidate for quantum information science benefitting from its long coherence time, high-fidelity gate operations. In addition, the ion photon entanglement provides a versatile tool to realize quantum networks by generating an ideal pair of a stationary memory qubit and a flying communication qubit. Rapid developments in nonlinear quantum frequency conversion techniques have enhanced the potential for constructing a trapped ion quantum network via optical fiber connections. The generation of long-distance entanglement has been demonstrated with ions such as Ca+ and Ba+, which emit photons in visible or near-infrared range naturally. On the other hand, as the qubit-native photons reside in ultra-violet (UV) spectrum, the Yb+ ion has not been considered as a strong competitor for telecommunication qubits despite extensive research on it. Here, we demonstrate an efficient difference-frequency conversion of UV photons, emitted from a trapped Yb+ ion, into a visible range. We provide experimental evidence that confirms the converted photons are radiated from the Yb+ ion. Our results provide a crucial step toward realizing a long-distance trapped ion quantum network based on Yb+ ions through quantum frequency conversion.

DOI: 10.1063/5.0241469

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