Research
Our strategies include the design and development of novel photonic structures and spectroscopic method to characterize light-matter interaction in molecular systems.
Light-Matter Interaction
Light-matter coupling strength (g) is associated with molecular transition dipoles and the electric field intensity. When the coupling strength is smaller than the dissipation rates {γ,κ}, the system is under weak coupling regime, where the light-matter interaction modifies spontaneous decay rates (Purcell effect). In contrast, the strong coupling regime emerges when the coupling strength exceeds the dissipation rates, molecules and photons start to hybridize, showing Rabi oscillations in population dynamics. This leads to the formation of new hybrid light–matter states— lower polaritonic state (LP) and upper polaritonic state (UP)—alongside a continuum of dark states.
Metasurface and Surface Lattice Resonance
To control light–matter interactions, we are developing metasurfaces designed to confine photonic modes. Metasurfaces consist of periodic subwavelength metallic or dielectric structures that resonantly interact with the electric and magnetic fields of incident electromagnetic waves, enabling unique properties characteristic of electromagnetic phenomena. Arrays of nanoparticles support surface lattice resonances (SLR), which arise from the coupling between the localized resonances of individual particles and their neighbors via the diffraction orders of the array. SLRs can enhance local field intensity on surfaces, giving rise to strong coupling, bound states in the continuum and chiroptical responses.
Quantum Electrodynamic Chemistry
Historically, scientists have elucidated the foundational principles of modern chemistry based on quantum mechanics. Within this framework, quantum electrodynamic (QED) effects have been considered negligible. However, recent experiments have demonstrated that under strong coupling conditions, QED effects can significantly influence chemical processes—modifying molecular self-assembly, altering reaction rates, and enabling selective control over reaction pathways. In our studies, we utilize SLRs modes in metasurfaces to manipulate chemical reactions and molecular optical properties.