UC Berkeley

Due to recent technological advances in the generation, manipulation, and detection of non-classical light, quantum light spectroscopy has gained attention as a candidate for expanding the current capabilities of classical laser light spectroscopy. In this dissertation, I develop an input-output formulation of quantum light spectroscopy by combining the input-output theory, traditionally used in the quantum optics community, with the perturbative expansion method for nonliear spectroscopy, traditionally used in the chemical physics community. Using this new spectroscopic formalism, we show that the optical signal in a class of quantum light spectroscopy experiments can be emulated by classical laser spectroscopy experiments. This class of quantum light spectroscopy experiments uses n = 0, 1, 2, · · · classical light pulses and an entangled photon pair (a biphoton state) where one photon acts as a reference without interacting with the matter sample.

To model the interaction between non-classical light and photosynthetic light harvesting systems, we develop a method to simulate the excitonic dynamics coupled to non-Markovian phonon degrees of freedom and to an N-photon Fock state pulse. This method combines the input-output and the hierarchical equations of motion (HEOM) formalisms into a double hierarchy of density matrix equations. We show analytically that, under weak field excitation relevant to natural photosynthesis conditions, an N-photon Fock state input and a corresponding coherent state input give rise to equal density matrices in the excited manifold. However, an N-photon Fock state input induces no off-diagonal coherence between the ground and excited subspaces, in contrast with the coherences created by a coherent state input. Detailed analysis of the absorption and emission behavior are discussed.