Bulletin of the American Physical Society
APS March Meeting 2020
Volume 65, Number 1
Monday–Friday, March 2–6, 2020; Denver, Colorado
Session F05: The Chemical Physics of Molecular Polaritons III. Vibrational Strong CouplingFocus Session
|
Hide Abstracts |
Sponsoring Units: DCP DCMP DPOLY Chair: Wei Xiong, University of California, San Diego Room: 111 |
Tuesday, March 3, 2020 8:00AM - 8:36AM |
F05.00001: Dynamics of Vibration-Cavity Polaritons Invited Speaker: Jeffrey Owrutsky Coupling vibrational modes to optical cavities results in vibration-cavity polaritons which can modify vibrational coherence and energy dynamics. Ultrafast infrared spectroscopy has been used to investigate vibration-cavity polaritons. We recently reported time resolved IR pump-probe studies on strongly-coupled vibration-cavity polaritons for tungsten hexacarbonyl (W(CO)6) in hexane in a Fabry-Pérot cavity [1]. The results demonstrated that while much of the response is due to so-called reservoir or uncoupled excited state absorption as well as polariton contraction, a component of the observed signals is due to polariton state evolution. We observe saturable absorption as nearly complete polariton contraction not only in pump probe measurements but also in single pulse studies.[2] 2DIR spectroscopy was used to provide evidence of hybrid light-matter polariton evolution and clear indications of direct excitation of dark states..[3] We have further expanded the investigation of vibrational dynamics for strongly coupled vibration-cavity polaritons to W(CO)6 in other solvents and to nitroprusside (Fe(CN)5NO2- in methanol. We explore salient features of the transient response, especially at short delay times, which show aspects of the response that are due to polaritons and are distinguished from uncoupled higher order excitations. |
Tuesday, March 3, 2020 8:36AM - 8:48AM |
F05.00002: Kinetic effects of vibrational polaritons in electron transfer. Jorge Campos Gonzalez Angulo, Raphael Ribeiro, Joel Yuen-Zhou Chemical kinetics has been modified for thermally activated reactions with molecules under vibrational strong light-matter coupling (VSC). These experiments are counterintuitive since VSC can only be achieved when a collectivity of vibrational modes (N ≈ 1010) simultaneously couples to a single confined electromagnetic mode, and, as a result, the normal modes consist of two polaritonic modes and N – 1 dark modes that behave as uncoupled vibrations. In this work, we show how VSC can induce catalysis in electron transfer, as described by the Marcus-Levich-Jortner formalism, by providing low activation energy channels that dominate the kinetics even when they are largely outnumbered by channels with unmodified activation energy. |
Tuesday, March 3, 2020 8:48AM - 9:00AM |
F05.00003: Molecular dipole moment drives the dynamics of vibrational polaritons in the strong and ultrastrong coupling regimes Johan Triana Galvis, Federico J. Hernández, Felipe Herrera Molecular polaritonics is a growing research topic both theoretically and experimentally. However, the underlying microscopic mechanisms for the modification of chemical reactions observed in experiments has yet to be fully understood. To improve our theoretical understanding, models such as the Holstein-Tavis-Cummings or the multi-level quantum Rabi model have been proposed to describe light-matter interaction between quantized fields and molecular transitions. In the strong coupling regime, effects induced by the light-matter coupling may have implications in the modification of chemical reactions, which demands an analysis beyond the RWA. We study the dynamics of anharmonic vibrational polaritons for polar (e.g. R-CO) and non-polar (e.g. CO2) molecules at equilibrium. We show that the electric dipole function strongly determines the dynamics of vibrational polaritons, and we describe such dependence in detail. Our results hint to a possible mechanism for cavity catalysis of chemical reactions under vibrational strong coupling and the spectroscopy of vibrational polaritons in liquid phase. In addition, our analysis could serve as a benchmark for future developments in the study of polariton chemistry in high-dimensional nuclear configuration spaces and multi-mode cavities. |
Tuesday, March 3, 2020 9:00AM - 9:12AM |
F05.00004: Strong Coupling of Terahertz Fields to Collective Intermolecular Vibrations Ran Damari, Omri Weinberg, Daniel Krotkov, Natalia Demina, Katherine Akulov, Adina Golombek, Sharly Fleischer, Tal Schwartz Several years ago, strong coupling of intra-molecular vibrations to mid-infrared resonators was introduced as a new paradigm in the field of polariton chemistry [1]. Such vibrational strong coupling allows the manipulation of molecular processes occurring at the electronic ground-state, by targeting a specific bond within the molecules [2]. |
Tuesday, March 3, 2020 9:12AM - 9:24AM |
F05.00005: Polariton-mediated vibrational ladder climbing Raphael Ribeiro, Joel Yuen-Zhou Vibrational ladder climbing (VLC) happens when a dipole-active molecular vibration is promoted to a highly excited-state by undergoing multiphoton absorption. Applications of this phenomenon include chemical reaction control via optical generation of non-equilibrium molecular excited-state populations with an increased probability of undergoing bond-breaking events. In this work, we present a theoretical treatment of VLC under strong infrared coupling, where the collective vibrational polarization efficiently exchanges energy reversibly with the electromagnetic field of an optical microcavity and hybrid light-matter excitations (polaritons) emerge. We focus on the basic principles of polariton-mediated VLC, including how its efficiency can be modulated by a proper choice of mesoscopic material, and conclude by discussing potential applications to reaction dynamics control, and spectroscopy of highly-excited states. |
Tuesday, March 3, 2020 9:24AM - 10:00AM |
F05.00006: Exploring Vibrational Polariton Dynamics with Ultrafast Two-Dimensional Infrared Spectroscopy Invited Speaker: Kevin Kubarych Vibrational strong coupling (VSC) offers a new approach to manipulate reaction thermodynamics, vibrational energy flow, and intermolecular interactions. The complex energy relaxation, transfer, and dephasing processes in vibrational polaritons are ideally suited for study by ultrafast infrared spectroscopy, particularly two-dimensional infrared (2D-IR), which has become a major tool to unravel vibrational dynamics in general. This talk will introduce and review the key principles and molecular observables central to 2D-IR, while demonstrating its application to a vibrational polariton system. For our first implementations of VSC we have chosen a tripodal transition metal carbonyl complex, methyl cycopentadienyl manganese tricarbonyl (MeCMT), which has two strong CO stretching bands near 2000 cm-1 separated by roughly 80 cm-1. Using a cavity with a free spectral range that closely matches this energy splitting, we establish strong coupling between the molecule and two adjacent cavity modes. The 2D-IR spectra show significant coupling between the two branches of polaritons, as well as extensive coherences and signatures for coherence transfer. |
Tuesday, March 3, 2020 10:00AM - 10:12AM |
F05.00007: Controling quantum pathways in the vibrational polaritons system Zimo Yang, Wei Xiong, Bo Xiang Molecular vibrational polaritons are hybrid quasi-particles between molecular vibrations and photons, through strong coherent light-matter coupling. It has attracted many attentions, because of its potential to alter photonic properties and also change the course of chemical reactions. Molecular vibrational polaritons have been studied by 2D infrared (2D IR) spectroscopy, which has advanced our understanding of the roles of dark states, hot excited state energy relaxation, and manipulation of nonlinear interactions in cavities. However, the coherent nature of polaritons imposes many quantum pathways contributing to the 2D IR signal, which complicates its interpretation and precision manipulation of quantum states. Using mid-IR pulse shaper, we report a way to selectively excite quantum pathways, to directly measure polariton nonlinear responses involving either coherence or population states. Because vibrational polariton forms a two-level system, it can serve a toy model to study the importance of coherence in energy transportation in energy materials. Thus, this work lays the foundation to prepare arbitrary quantum states in polaritons, for further exploration of the phenomena of nonlinear photonics, chemistry and quantum phenomena. |
Tuesday, March 3, 2020 10:12AM - 10:24AM |
F05.00008: Remote of chemistry in optical cavities Matthew Du, Raphael Ribeiro, Joel Yuen-Zhou Quantum states in different molecules can be hybridized by strong light-matter interaction. This phenomenon has been previously harnessed to realize long-range energy transfer between organic chromophores separated by optical length scales. Here, we propose a remote control of chemistry whereby photoexcitation of molecules in one optical microcavity influences the photochemical reactivity of molecules in another microcavity. For the infrared-induced cis-to-trans conformational isomerization of nitrous acid (HONO), we show that the proposed strategy leads to enhancement of the reaction efficiency by an order of magnitude. |
Tuesday, March 3, 2020 10:24AM - 10:36AM |
F05.00009: Cavity-Modified Chemical Reaction Kinetics and Electrochemical Modulation of Coupling Strength Blake Simpkins, Wonmi Ahn, Adam Dunkelberger, Andrea Grafton, Jeremy Pietron, Kenan Fears, Jeffrey Owrutsky Quantum emitters strongly coupled to optical cavities exchange energy inextricably, creating new hybrid polaritons. Recently, this half-light half-matter quasi-state has been demonstrated with molecular vibrations coherently coupled to optical modes. In this talk, we discuss (1) cavity-modified chemical reactivity and (2) modulation of the strong coupling phenomenon via electrochemical reaction. Specifically, we monitor transmission of a Fabry-Pérot microcavity filled with reactive species. Both reactants and products have strong molecular vibrations that couple to the optical cavity modes. We compare reaction rates in and out of the cavity to expose the influence of vibrational strong coupling on reaction kinetics. Secondly, we evaluate electrochemical switching of cavity coupling magnitude in both the visible and infrared regimes. Our results demonstrate full modulation of the Rabi splitting, a diffusion-limited redox process, and imaging of molecular adsorption/desorption processes on the metal surface. These results have important implications for chemical synthesis and catalysis. |
Tuesday, March 3, 2020 10:36AM - 10:48AM |
F05.00010: Ultrastrong coupling in hexagonal Boron Nitride microcavities Unai Muniain, Maria Barra-Burillo, Ruben Esteban, Sara Catalano, Marta Autore, Luis Hueso, Rainer Hillenbrand, Javier Aizpurua When the interaction between light and matter is very efficient, it is possible to attain the regime of ultrastrong coupling (USC), where a variety of quantum effects of considerable interest can be revealed [1]. In this contribution, we study an infrared Fabry-Perót microcavity formed by metallic mirrors, filled with hexagonal Boron Nitride (hBN) acting as a phononic material [2]. The optical response obtained within a transfer-matrix approacimation can be interpreted with the use of a semi-classical model of coupled harmonic oscillators. As a consequence of the large Reststrahlen band of hBN, the Rabi splitting obtained is of the order of the frequencies of the bare cavity and the phonons. The system is thus in the USC regime. We also show that the calculations are in excellent agreement with experimental measurements, which suggests the interest of this configuration as a practical setup to explore USC. |
Tuesday, March 3, 2020 10:48AM - 11:00AM |
F05.00011: Resonant Rayleigh Scattering from Collective Molecular Excitations Mukundakumar Balasubrahmaniyam, Adina Golombek, Maria Kaeek, Keren Hadar, Tal Schwartz Resonant Rayleigh scattering (RRS) is the pronounced elastic scattering of photons present at the vicinity of the natural resonances of sub-wavelength physical objects such as molecules, which otherwise scatter negligibly. Here, we study RRS from molecular ensembles strongly coupled to an optical microcavity. Under these conditions, the coherent interaction between the molecules and the cavity mode produces collective molecular states known as cavity polaritons and which can drastically modify the properties these molecules. Our spectroscopic measurements reveal that strong RRS occurs at the polaritonic energies, reaching ~25% efficiency. Interestingly, this resonant scattering corresponds to the collective scattering of each photon from a macroscopically-large ensemble of molecules, rather than the scattering by individual ones, as in the usual case. We show that the scattering from the polaritonic states exhibit non trivial behaviors, specifically a linear dependence of the scattering strength on their photonic component. We believe that these observations, together with further investigation, may lead to a deeper understanding of these delocalized, collective molecular excitations, their non-equilibrium transport and the role of disorder in their dynamics. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2025 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700