  Physical systems with discrete energy levels are ubiquitous in nature and are
fundamental building blocks of quantum technology. Realizing controllable
artifcial atom- and molecule-like systems for light would allow for coherent
and dynamic control of the frequency, amplitude and phase of photons. In this
work, we demonstrate a photonic molecule with two distinct energy-levels and
control it by external microwave excitation. We show signature two-level
dynamics including microwave induced photonic Autler-Townes splitting, Stark
shift, Rabi oscillation and Ramsey interference. Leveraging the coherent
control of optical energy, we show on-demand photon storage and retrieval in
optical microresonators by reconfguring the photonic molecule into a
bright-dark mode pair. These results of dynamic control of light in a
programmable and scalable electro-optic platform open doors to applications in
microwave photonic signal processing, quantum photonics in the frequency
domain, optical computing concepts and simulations of complex physical systems.
