62 research outputs found
Coherent coupling of molecular resonators with a micro-cavity mode
The optical hybridization of the electronic states in strongly coupled
molecule-cavity systems have revealed unique properties such as lasing, room
temperature polariton condensation, and the modification of excited electronic
landscapes involved in molecular isomerization. Here we show that molecular
vibrational modes of the electronic ground state can also be coherently coupled
with a micro-cavity mode at room temperature, given the low vibrational thermal
occupation factors associated with molecular vibrations, and the collective
coupling of a large ensemble of molecules immersed within the cavity mode
volume. This enables the enhancement of the collective Rabi-exchange rate with
respect to the single oscillator coupling strength. The possibility of inducing
large shifts in the vibrational frequency of selected molecular bonds should
have immediate consequences for chemistry.Comment: 22 pages, 6 figures (including Supplementary Information file
Tilting a ground-state reactivity landscape by vibrational strong coupling
Many chemical methods have been developed to favor a particular product in transformations of compounds that have two or more reactive sites. We explored a different approach to site selectivity using vibrational strong coupling (VSC) between a reactant and the vacuum field of a microfluidic optical cavity. Specifically, we studied the reactivity of a compound bearing two possible silyl bond cleavage sites—Si–C and Si–O, respectively—as a function of VSC of three distinct vibrational modes in the dark. The results show that VSC can indeed tilt the reactivity landscape to favor one product over the other. Thermodynamic parameters reveal the presence of a large activation barrier and substantial changes to the activation entropy, confirming the modified chemical landscape under strong coupling
Figure-of-merit enhancement of surface plasmon resonance sensors in the spectral interrogation
We show that adding a thin dielectric layer with high refractive index on top of the metallic layer in surface plasmon resonance sensors in the Kretschmann–Raether configuration in the spectral mode causes a redshift of the resonance wavelength, narrowing of the resonance dip, and an enhancement to the spectral sensitivity. Surprisingly, together with the sensitivity enhancement, the dip becomes much narrower and the figure of merit is considerably improved, particularly in the IR range.Published versio
Ground-State Chemical Reactivity under Vibrational Coupling to the Vacuum Electromagnetic Field
The ground-state deprotection of a simple alkynylsilane is studied under vibrational strong coupling to the zero-point fluctuations, or vacuum electromagnetic field, of a resonant IR microfluidic cavity. The reaction rate decreased by a factor of up to 5.5 when the Si-C vibrational stretching modes of the reactant were strongly coupled. The relative change in the reaction rate under strong coupling depends on the Rabi splitting energy. Product analysis by GC-MS confirmed the kinetic results. Temperature dependence shows that the activation enthalpy and entropy change significantly, suggesting that the transition state is modified from an associative to a dissociative type. These findings show that vibrational strong coupling provides a powerful approach for modifying and controlling chemical landscapes and for understanding reaction mechanisms
Quantum Strong Coupling with Protein Vibrational Modes
In
quantum electrodynamics, matter can be hybridized to confined
optical fields by a process known as light–matter strong coupling.
This gives rise to new hybrid light–matter states and energy
levels in the coupled material, leading to modified physical and chemical
properties. Here, we report for the first time the strong coupling
of vibrational modes of proteins with the vacuum field of a Fabry–Perot
mid-infrared cavity. For two model systems, polyÂ(l-glutamic
acid) and bovine serum albumin, strong coupling is confirmed by the
anticrossing in the dispersion curve, the square root dependence on
the concentration, and a vacuum Rabi splitting that is larger than
the cavity and vibration line widths. These results demonstrate that
strong coupling can be applied to the study of proteins with many
possible applications including the elucidation of the role of vibrational
dynamics in enzyme catalysis and in H/D exchange experiments
Correction to Vibro-Polaritonic IR Emission in the Strong Coupling Regime
Correction to ACS Photonics 2018, 5 (1), 217-224: The method of fitting the microcavity transmission spectrum to derive the cavity absorption spectrum by means of transfer-matrix analysis was flawed. Consequently, in contrast to our initial conclusions, the polaritonic emission appears thermalized and there is no evidence for polariton emission that is blue-shifted with respect to the polariton absorption. For this reason, the interpretation of the blue-shift as a signature of polariton–polariton interactions is obsolete
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