Characterization of A Novel 2D-3D Photonic Integrated Circuit for Broadband, High-Efficiency Control of Trapped Ion Qubit Arrays*

Photonics integration offers a promising path toward scalable quantum processors. We designed, fabricated, and optically characterized a monolithic surface trap with a novel integrated photonic circuit layer that achieves near-perfectly achromatic beam focusing over a wavelength range from 405 nm to 950 nm, using a planar waveguide lens paired with a 3D-printed biconic mirror. Additionally, our device exhibits close to 40 dB crosstalk suppression at the Ca40 optical gate wavelength of 729 nm, assuming a 5 um ion-ion distance. To characterize the properties of this trap, we simulated the dielectric-induced surface noise of the trap. Additionally, we assessed the trapping potential using boundary element methods to evaluate the impact of the integrated photonics layer on trapping performance. Experimentally, we are working towards ion trapping on the integrated photonics trap in a UHV chamber, with beam delivery of lasers required for Ca+ trapping, cooling and state manipulation integrated on chip via a fiber feedthrough.