Ultrafast photodynamics of molecular polaritons analyzed with nonlinear multidimensional spectroscopies

José Luis Sanz-Vicario Universidad de Antioquia

n recent experiments J-aggregates of organic dye molecules immersed in optical Fabry-Perot microcavities are subject to the strong coupling interaction between the matter and the quantized light field [1]. New entangled polariton states result from the hybridation between molecular states (electronic and vibrational) and cavity photon states. To model the electronic and nuclear molecular structure of an ensemble of molecules inside a cavity and its related photodynamics from first principles is by today’s computacional capability a formidable task. Parameterized models in quantum optics like the Jaynes-Cummings Hamiltonian for a single emitter, the Tavis- Cummings Hamiltonian for a collective of emitters and the Holstein-Tavis-Cummings (including vibrational states) have served well to understand the fundamental physics of atomic and molecular emitters in cavities. In addition, these dressed-by-light emitters are subject to dissipative processes due to cavity photon losses, intra- or inter-molecular vibrational relaxation, solvent or phonon effects if aggregates are in liquid solution or in solid matrices, respectively. It implies to deal with an open quantum system coupled to a complex thermal bath.

In this work we present a scrutinized study of the ultrafast photodynamics of an ensemble of molecular polaritons by using nonlinear coherent two- dimensional spectroscopy, for which we have recently introduced a very efficient computational method of solution [2] and we show that the role of uncoupled dark states cannot be underestimated.

[1] L. Mewes et al, Comunn. Phys. 3, 157 (2020).

[2] D. Gallego-Valencia, L. Mewes, J. Feist and J. L. Sanz-Vicario, Phys Rev. A 109, 063704 (2024)