All-optical trapping of strongly coupled ions

Jack Morphew

Precise control over internal states of atomic ions in ion traps has been possible for many years enabling high precision spectroscopy of atomic transitions. Trapped ions are suitable candidates for quantum information processing due to their long storage times, low decoherence rates and high readout efficiency. Recent advances in micro-machining fibre optic mirrors and integrated fibre optic-ion trap systems for cavity QED allows one to realise strong coupling between an ion and a cavity mode by reducing the mode volume. For strong ion-cavity coupling, deterministic transfer of quantum states between ions and photons is possible. We have designed and constructed a miniaturised linear Paul trap with an integrated optical cavity, intended for coupling multiple ions to the cavity mode. The RF-electrode separation is 50μm, while the endcap separation is 350μm. The endcap electrodes are narrow tubes of inner diameter 300μm allowing optical fibers through the tubes to form the cavity. The trap depth we calculate to be 650meV for a 10V applied potential at 20MHz. The 4P1⁄2→ 3D3⁄2 transition of the atomic ion 40Ca+ with Γ = 24π × 22MHz can be coupled to an optical fibre Fabry-Perot cavity with length of 380µm, finesse of 33,000 and cavity linewidth k = 2π ×11MHz.The ion-cavity coherent coupling g = 2π × 19:5MHz of this system will put it in single-ion strong coupling regime with cooperativity, C=1.5.

Ch. Schneider, Martin Enderlein, Thomas M. Huber +1 more

Benjamin P. Stein

Marko Cetina, Alexei Bylinskii, Leon Karpa +7 more

We present a novel system where an optical cavity is integrated with a microfabricated planar-electrode ion trap. The trap electrodes produce a tunable periodic potential allowing the trapping of up to 50 separate ion chains aligned with the cavity and spaced by 160 μ m in a one-dimensional array along the cavity axis. Each chain can contain up to 20 individually addressable Yb + ions coupled to the cavity mode. We demonstrate deterministic distribution of ions between the sites of the electrostatic periodic potential and control of the ion–cavity coupling. The measured strength of this coupling should allow access to the strong collective coupling regime with ≲10 ions. The optical cavity could serve as a quantum information bus between ions or be used to generate a strong wavelength-scale periodic optical potential.

Marko Cetina, Alexei Bylinskii, Leon Karpa +7 more

We present a novel system where an optical cavity is integrated with a microfabricated planar-electrode ion trap. The trap electrodes produce a tunable periodic potential allowing the trapping of up to 50 separate ion chains aligned with the cavity and spaced by 160 μm in a one-dimensional array along the cavity axis. Each chain can contain up to 20 individually addressable Yb+ ions coupled to the cavity mode. We demonstrate deterministic distribution of ions between the sites of the electrostatic periodic potential and control of the ion-cavity coupling. The measured strength of this coupling should allow access to the strong collective coupling regime with 10 ions. The optical cavity could serve as a quantum information bus between ions or be used to generate a strong wavelength-scale periodic optical potential. © IOP Publishing and Deutsche Physikalische Gesellschaft.

Wayne M. Itano, Jonas Bergquist, F. Diedrich +1 more