Polariton Transitions in Femtosecond Transient Absorption Studies of Ultrastrong Light-Molecule Coupling

Courtney A. Delpo, Bryan Kudisch, Kyu Hyung Park, Saeed Uz Zaman Khan, Francesca Fassioli, Daniele Fausti, Barry P. Rand, Gregory D. Scholes

Research output: Contribution to journalArticlepeer-review

57 Scopus citations


Strong light-matter coupling is emerging as a fascinating way to tune optical properties and modify the photophysics of molecular systems. In this work, we studied a molecular chromophore under strong coupling with the optical mode of a Fabry-Perot cavity resonant to the first electronic absorption band. Using femtosecond pump-probe spectroscopy, we investigated the transient response of the cavity-coupled molecules upon photoexcitation resonant to the upper and lower polaritons. We identified an excited state absorption from upper and lower polaritons to a state at the energy of the second cavity mode. Quantum mechanical calculations of the many-molecule energy structure of cavity polaritons suggest assignment of this state as a two-particle polaritonic state with optically allowed transitions from the upper and lower polaritons. We provide new physical insight into the role of two-particle polaritonic states in explaining transient signatures in hybrid light-matter coupling systems consistent with analogous many-body systems.

Original languageEnglish (US)
Pages (from-to)2667-2674
Number of pages8
JournalJournal of Physical Chemistry Letters
Issue number7
StatePublished - Apr 2 2020

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • Physical and Theoretical Chemistry


Dive into the research topics of 'Polariton Transitions in Femtosecond Transient Absorption Studies of Ultrastrong Light-Molecule Coupling'. Together they form a unique fingerprint.

Cite this