Addressing Trapped Ions with Semiconductor Optical Waveguides

Quantum computing (QC) is theorized to solve certain important problems much faster than classical computers. However, the current state of QC, the noisy intermediate-scale quantum (NISQ) era, is limited in the scope of problems it can solve, largely due to the quantity of reliable qubits available to universal quantum operations. And while all available quantum computing systems have their advantages, ion-based systems have been shown to be a reliable option with low infidelity and a capability for universal gating procedure. These advantages are dependent on achieving low crosstalk when addressing ions, a vital challenge for this QC system, particularly when using only bulk optic systems. Here we show a microfabricated planar waveguide which can selectively interact in free space with 8 trapped Ba+ ions. The imaged light is characterized by a spatial scan of the chip and PMT counts from the fluorescence of Ba+ ions from the intended mode of operation with low crosstalk measured by both methods. This performance meets or exceeds that of similar waveguides couple to trapped ion systems and shows a reliable method to selectively interact with ions bound by a Paul Trap using imaged waveguide outputs

Distribution Statement A: Approved for Public Release; Distribution Unlimited: AFRL-2023-0551