Presentation of Ph.D. Thesis

Recent advances in encoding qubits in microwaves have spurred the need for
coherent microwave-to-optical transduction. Intense efforts are being made to
tailor physical systems in a miniaturized and silicon-compatible platform to
effect this transduction process. Demonstrations of this conversion have been
made using electro-optics, optomechanics, and excited state Rydberg atomic
systems. This thesis is both an experimental and theoretical study of microwave-
to-optical transduction using room temperature, ground state neutral Rb atoms
in a small vapor cell.

This thesis will address the challenges for microwave-to-optical transduction
using a three-level atomic scheme at room temperature. Our research focuses on
coherent interactions of lasers and microwaves with the hyperfine levels of 85Rb
in the D1 manifold. The closed cyclic structure of the interactions makes the
system phase sensitive and provides a handle to modulate the microwave phase
in order to regulate the intensity of one of the lasers. This phase-to-intensity
correlation makes the system a radio-over-fibre device. Additionally, by invoking
a hybrid second-order nonlinearity possessed by this atomic scheme a platform
for pulse-on-demand can be designed. Importantly, the pulse can be delayed
or advanced by controlling the intensity of the microwave. The simultaneous
observation of three-wave mixing (TWM) and six-wave mixing (SWM) processes
in the same system will also be discussed.