Mapping Molecular Polariton Transport via Pump-Probe Microscopy

Area of Science:

• Condensed Matter Physics
• Quantum Optics
• Spectroscopy

Background:

• Molecular polaritons are hybrid light-matter quasiparticles confined in optical cavities.
• Understanding their transport properties is crucial for developing novel optoelectronic devices.
• Current methods often lack the resolution to fully characterize complex transport dynamics.

Purpose of the Study:

• To develop a microscopic modeling approach for extracting molecular polariton transport properties.
• To extend semiclassical cavity spectroscopy to multimode light-matter interactions.
• To analyze the influence of molecular dephasing and exciton populations on polariton transport.

Main Methods:

• Mean-field treatment of the light-matter Hamiltonian.
• Perturbative expansion of light and matter components.
• Spatial coarse-graining and simulation of pump-probe microscopy experiments.

Main Results:

• Computed differential transmission spectra revealing spatially resolved transient dynamics.
• Demonstrated that molecular dephasing and dark excitons drive polariton subgroup velocity transport.
• Correlated velocity renormalization with excitonic weight and dephasing rates.

Conclusions:

• The developed model provides full access to spatially resolved transient spectra.
• Spectroscopic observables are essential for characterizing transport in polaritonic systems.
• Transport velocity is tunable via molecular dephasing, exciton hopping, and annihilation rates.