Integrated-Photonics Devices and Architectures for Advanced Cooling of Trapped Ions

Abstract

Integrated-photonics-based architectures for trapped-ion systems offer a potential avenue for improved fidelity and addressability of ion arrays. Motional state cooling, a key optical function in trapped-ion systems, however, has been limited to Doppler and resolved-sideband cooling in integrated-photonics-based implementations. In contrast, polarization-gradient and electromagnetically-induced-transparency cooling can offer better cooling performance in multi-ion systems, but have not been demonstrated on an integrated-photonics platform. This thesis demonstrates key integrated-photonics devices and architectures to enable enhanced laser cooling of integrated trapped-ion systems.

First, we develop the framework for two advanced trapped-ion cooling schemes, polarization-gradient and electromagnetically-induced-transparency cooling. Then, we present the design of key integrated devices enabling the proposed system architectures. First, we show the design and experimental demonstration of the first integrated polarization splitters and rotators at blue wavelengths. We develop compact and efficient designs for both a polarization splitter and rotator at a 422-nm wavelength, an important transition for 88Sr+ ions. These devices are fabricated in a 200-mm wafer-scale process and experimental results are demonstrated. Next, we present the design and experimental demonstration of the first pair of integrated TE- and TM-emitting gratings at a wavelength of 422 nm to enable polarization-diverse operations for integrated-photonics-based trapped-ion systems. The development of both the devices and architectures for advanced cooling schemes presented in this thesis paves the way for sophisticated integrated control for trapped-ion and neutral-atom systems.