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Moritaka SS, Lebedev VS. Orientational effects in the polarized absorption spectra of molecular aggregates. J Chem Phys 2024; 160:074901. [PMID: 38364011 DOI: 10.1063/5.0188128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Accepted: 01/23/2024] [Indexed: 02/18/2024] Open
Abstract
We present a detailed theoretical analysis of polarized absorption spectra and linear dichroism of cyanine dye aggregates whose unit cells contain two molecules. The studied threadlike ordered system with a molecular exciton delocalized along its axis can be treated as two chains of conventional molecular aggregates, rotated relative to each other at a certain angle around the aggregate axis. Our approach is based on the general formulas for the effective cross section of light absorption by a molecular aggregate and key points of the molecular exciton theory. We have developed a self-consistent theory for describing the orientational effects in the absorption and dichroic spectra of such supramolecular structures with nonplanar unit cell. It is shown that the spectral behavior of such systems exhibits considerable distinctions from that of conventional cyanine dye aggregates. They consist in the strong dependence of the relative intensities of the J- and H-type spectral bands of the aggregate with a nonplanar unit cell on the angles determining the mutual orientations of the transition dipole moments of constituting molecules and the aggregate axis as well as on the polarization direction of incident light. The derived formulas are reduced to the well-known analytical expressions in the particular case of aggregates with one molecule in the unit cell. The calculations performed within the framework of our excitonic theory combined with available vibronic theory allow us to quite reasonably explain the experimental data for the pseudoisocyanine bromide dye aggregate.
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Affiliation(s)
- S S Moritaka
- P. N. Lebedev Physical Institute of Russian Academy of Sciences, 53 Leninskiy Prosp., 119991 Moscow, Russian Federation
| | - V S Lebedev
- P. N. Lebedev Physical Institute of Russian Academy of Sciences, 53 Leninskiy Prosp., 119991 Moscow, Russian Federation
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Mondal ME, Koessler ER, Provazza J, Vamivakas AN, Cundiff ST, Krauss TD, Huo P. Quantum dynamics simulations of the 2D spectroscopy for exciton polaritons. J Chem Phys 2023; 159:094102. [PMID: 37655761 DOI: 10.1063/5.0166188] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 08/10/2023] [Indexed: 09/02/2023] Open
Abstract
We develop an accurate and numerically efficient non-adiabatic path-integral approach to simulate the non-linear spectroscopy of exciton-polariton systems. This approach is based on the partial linearized density matrix approach to model the exciton dynamics with explicit propagation of the phonon bath environment, combined with a stochastic Lindblad dynamics approach to model the cavity loss dynamics. Through simulating both linear and polariton two-dimensional electronic spectra, we systematically investigate how light-matter coupling strength and cavity loss rate influence the optical response signal. Our results confirm the polaron decoupling effect, which is the reduced exciton-phonon coupling among polariton states due to the strong light-matter interactions. We further demonstrate that the polariton coherence time can be significantly prolonged compared to the electronic coherence outside the cavity.
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Affiliation(s)
- M Elious Mondal
- Department of Chemistry, University of Rochester, Rochester, New York 14627, USA
| | - Eric R Koessler
- Department of Chemistry, University of Rochester, Rochester, New York 14627, USA
| | - Justin Provazza
- Quantum Simulation Technologies, Inc., Boston, Massachusetts 02135, USA
| | - A Nickolas Vamivakas
- The Institute of Optics, Hajim School of Engineering, University of Rochester, Rochester, New York 14627, USA
- Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA
| | - Steven T Cundiff
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Todd D Krauss
- Department of Chemistry, University of Rochester, Rochester, New York 14627, USA
- The Institute of Optics, Hajim School of Engineering, University of Rochester, Rochester, New York 14627, USA
| | - Pengfei Huo
- Department of Chemistry, University of Rochester, Rochester, New York 14627, USA
- The Institute of Optics, Hajim School of Engineering, University of Rochester, Rochester, New York 14627, USA
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Engelhardt G, Cao J. Polariton Localization and Dispersion Properties of Disordered Quantum Emitters in Multimode Microcavities. PHYSICAL REVIEW LETTERS 2023; 130:213602. [PMID: 37295110 DOI: 10.1103/physrevlett.130.213602] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 04/07/2023] [Indexed: 06/12/2023]
Abstract
Experiments have demonstrated that the strong light-matter coupling in polaritonic microcavities significantly enhances transport. Motivated by these experiments, we have solved the disordered multimode Tavis-Cummings model in the thermodynamic limit and used this solution to analyze its dispersion and localization properties. The solution implies that wave-vector-resolved spectroscopic quantities can be described by single-mode models, but spatially resolved quantities require the multimode solution. Nondiagonal elements of the Green's function decay exponentially with distance, which defines the coherence length. The coherent length is strongly correlated with the photon weight and exhibits inverse scaling with respect to the Rabi frequency and an unusual dependence on disorder. For energies away from the average molecular energy E_{M} and above the confinement energy E_{C}, the coherence length rapidly diverges such that it exceeds the photon resonance wavelength λ_{0}. The rapid divergence allows us to differentiate the localized and delocalized regimes and identify the transition from diffusive to ballistic transport.
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Affiliation(s)
- Georg Engelhardt
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jianshu Cao
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
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