Ultrafast non-adiabatic molecular energy conversion into photons induced by quantized electromagnetic fields

Area of Science:

• Quantum optics
• Molecular dynamics
• Nanophotonics

Background:

• Molecular polaritons in the mid-infrared regime offer ways to tune molecular and photonic properties.
• Developing novel photon generation methods remains a challenge in nanophotonics.

Purpose of the Study:

• To investigate ultrafast photodynamics of diatomic molecules in confined electromagnetic fields.
• To explore photon generation mechanisms using a molecular model incorporating realistic couplings.

Main Methods:

• Utilized the Holstein-quantum-Rabi Hamiltonian with realistic dipole moments and nonadiabatic couplings.
• Studied diatomic molecules within quantized cavities and confined electromagnetic fields.
• Analyzed polariton photodynamics in a femtosecond timescale, excluding dissipative effects.

Main Results:

• Identified two types of light-induced crossings, including those involving counter-rotating transitions.
• Observed significant changes in the polariton energy spectrum with the Huang-Rhys factor when nonadiabatic couplings were included.
• Demonstrated the crucial role of nonadiabatic and counter-rotating couplings in vibronic energy to photon conversion.

Conclusions:

• Nonadiabatic molecular couplings and cavity-molecule counter-rotating couplings are vital for photon generation.
• The sign of the Huang-Rhys factor significantly influences photon conversion efficiency.
• This research supports the development of many-photon generation through strong light-matter interactions, with potential applications in alkaline earth monohydride molecules.