Strong Coupling of a Single Ion to an Optical Cavity

Abstract

Strong coupling between an atom and an electromagnetic resonator is an important condition in cavity quantum electrodynamics (QED). While strong coupling in various physical systems has been achieved so far, it remained elusive for single atomic ions. In this paper we demonstrate for the first time the coupling of a single ion to an optical cavity with a coupling strength exceeding both atomic and cavity decay rates. We use cavity assisted Raman spectroscopy to precisely characterize the ion-cavity coupling strength and observe a spectrum featuring the normal mode splitting in the cavity transmission due to the ion-cavity interaction. Our work paves the way towards new applications of cavity QED utilizing single trapped ions in the strong coupling regime for quantum optics and quantum technologies.

Shuttling-based trapped-ion quantum information processing

“…Optical interfaces are a possible means for interconnecting the nodes within such an array, and could be based on free-space or cavity-enhanced coupling to optical radiation. Several research groups have realized free-space 23,105,106 optical interfaces, and work on cavity-based optical interfaces is ongoing 33,107,108 . Another approach could be to combine segmented linear traps with the extraction of single ions 109 from one trap and its injection 110 into a second ion trap.…”

Optimized single-shot laser ablation of concave mirror templates on optical fibers

“…Fiber-based Fabry-Perot optical microcavities are widely used in the fields of CQED [12][13][14][15][16][17][18][19]33,34] and optomechanics [20][21][22][23], with additional applications in sensing [44][45][46]. A figure of merit common to most of these applications is the ratio between the finesse F of the cavity and the crosssection πw 2 0 of the fundamental mode of the cavity, which we define here as FOM = F /(πw 2 0 ).…”

“…Over the past few years, the main focus of research on CO 2 laser ablation of mirror templates on optical fibers has been developing multi-shot ablation procedures in order to achieve better control over the geometry of the concave shape [24][25][26][27]. These studies, alongside with improved analytical and numerical cavity models [28][29][30][31][32], notably contributed to recent breakthroughs in trapped ion CQED [33], trapped atom CQED [34], solid-state QED [35], and optomechanics [36]. Nevertheless, a systematic study of the effects of fabrication parameters on the geometrical characteristics of structures created by a single ablation pulse has not yet been reported.…”

Enhanced ion–cavity coupling through cavity cooling in the strong coupling regime

“…Incorporating optical cavities into ion traps merges the outstanding properties of ions such as long coherence times 1 and high-fidelity quantum control 2 with the means to deterministically transfer the quantum state between ions and light at the single quantum level. Exploiting this superior control, cavity induced transparency 3 , the mapping of the quantum state between ions and photons 4 , ion-photon entanglement 5 and heralded ion-ion entanglement 6 have been demonstrated. Ion-cavity systems enable distributed architectures for large-scale quantum information processing as well as device-independent quantum key distribution.…”

“…Ion-cavity systems enable distributed architectures for large-scale quantum information processing as well as device-independent quantum key distribution. Instrumental to these applications is the ability to localise ions in optical cavities [7][8][9][10] and to strongly couple single ions to an optical cavity 3 .…”