Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Ensembles of single-molecule picocavities as nonlinear optical metamaterials

Felipe Herrera, Marina Litinskaya

Published Apr 2, 2021• 0 citations
OpenAlex

Abstract

Strong coupling with single molecules in plasmonic picocavities has emerged as a resource for room-temperature quantum control with nanoscale light. Tip-based nanoprobes can measure the local dynamics of individual molecular picocavities, but the overhead associated with sampling an inhomogeneous picocavity distribution can be challenging for scalability. We propose a macroscopic approach in which an ensemble of molecular picocavities acts as a nonlinear plasmonic metamaterial. Using a quantum optics perspective, we study theoretical performance limits for optical cross-phase modulation in the system, taking into account realistic distributions of picocavity volumes and molecular transition frequencies. The medium nonlinearity is mediated by local strong coupling with the lowest vibronic emission sideband of individual organic chomophores. The local vacua change the refractive index of the medium at the frequency of a weak probe field $\omega_p$, set to drive the bare zero-phonon absorption band. Refractive index variations $\Delta n/n$ of a few percent, relative to a molecule-free scenario, are feasible with dilute ensembles. The probe phase evolution can be switched off in the presence of a signal field at a higher frequency $\omega_s$, for intensities as low as 10 kW/cm$^2$. The mechanism for optical switching involves a novel ($\omega_p+\omega_s$) two-photon absorption channel, assisted by local vacuum fields. Our work paves the way for future studies of plasmonic metamaterials that exploit strong light-molecule interactions, for applications in optical state preparation and control.

Related papers

Disordered ensembles of strongly coupled single-molecule plasmonic picocavities as nonlinear optical metamaterials

Felipe Herrera, Marina Litinskaya

We propose to use molecular picocavity ensembles as macroscopic coherent nonlinear optical devices enabled by nanoscale strong coupling. For a generic picocavity model that includes molecular and photonic disorder, we derive theoretical performance bounds for coherent cross-phase modulation signals using weak classical fields of different frequencies. We show that strong coupling of the picocavity vacua with a specific vibronic sideband in the molecular emission spectrum results in a significant variation of the effective refractive index of the metamaterial relative to a molecule-free scenario due to a vacuum-induced Autler–Townes effect. For a realistic molecular disorder model, we demonstrate that cross-phase modulation of optical fields as weak as 10 kW/cm2 is feasible using dilute ensembles of molecular picocavities at room temperature, provided that the confined vacuum is not resonantly driven by the external probe field. Our work paves the way for the development of plasmonic metamaterials that exploit strong coupling for optical state preparation and quantum control.

arXiv:2104.00852•The Journal of Chemical Physics•Mar 17, 2022•11 citations

Controlled cavity quantum electrodynamics with molecular ensembles in infrared nanocavities

Felipe Herrera, Johan F. Triana, Mauricio Arias +6 more

Molecular ensembles in confined infrared (IR) fields have emerged as a promising platform for condensed-phase cavity QED at room temperature, for the development of scalable architectures for IR quantum optics also at the nanoscale. We develop a Markovian open quantum system approach to study the dynamics of molecular vibrations in infrared nanocavities under femtosecond pulse driving, as implemented in recent nanoprobe spectroscopy experiments with polymer-coated IR gold antennas. We describe the time-domain signatures of the crossover from weak to strong coupling regimes in these nanocavities, provide mechanistic insights on the conditions for implementing coherent phase-space rotations of the nanocavity field using a tip nanoprobe, and discuss the tunable role of molecular anharmonicity as a function of pump power. Our work offers microscopic design strategies for quantum state preparation and control with emitter-nanocavity hybrids using infrared quantum optics.

Metamaterials, Metadevices, and Metasystems•Jul 30, 2021•0 citations

Picocavity-controlled Sub-nanometer Resolved Single Molecule Non-linear Fluorescence

Lyu, Siyuan, Yuan Zhang, Yao Zhang +3 more

In this article, we address fluorescence of single molecule inside a plasmonic picocavity by proposing a semi-classical theory via combining the macroscopic quantum electrodynamics theory and the open quantum system theory. To gain insights into the experimental results [Nat. Photonics, 14, 693 (2020)], we have further equipped this theory with the classical electromagnetic simulation of the pico-cavity, formed by single atom decorated silver STM tip and a silver substrate, and the time-dependent density functional theory calculation of zinc phthalocyanine molecule. Our simulations not only reproduce the fluorescence spectrum as measured in the experiment, confirming the influence of extreme field confinement afforded by the picocavity, but also reveal Rabi oscillation dynamics and Mollow triplets spectrum for moderate laser excitation. Thus, our study highlights the possibility of coherently manipulating the molecular state and exploring non-linear optical phenomena with the plasmonic picocavity.

arXiv:2112.09554•Dec 17, 2021•0 citations

Coherent Coupling of Single Organic Dye Molecules to Optical Nanoguides

Pierre Türschmann

Optical studies of single emitters have become routine for a number of systems ranging from atoms and ions in the gas phase to molecules, color centers and quantum dots in the solid-state. A new direction in experimental quantum optics is to exploit this know-how to assemble well-defined arrangements of optically coupled emitters for investigating quantum many-body physics. However, common approaches via strong focusing or cavity quantum electrodynamics do not scale favorably. We developed a scalable light-matter interface by coupling organic dye molecules to subwavelength dielectric waveguides (nanoguides). Their small effective mode area gives rise to substantial single-emitter coupling efficiencies with expected values up to 35%. By combining high-resolution microscopy with fluorescence excitation and resonance fluorescence spectroscopy, we study the coupled nano-guide-emitter system. Our results demonstrate the versatility of the geometry for reaching high optical densities and yet maintaining the addressability of each single emitter. We show that we can couple several thousand molecules simultaneously and coherently to a single guided mode, while their nearly lifetime-limited resonances are inhomogeneously distributed. The optical response of the coupled nanoguide-emitter system can be controlled by modifying the molecular electronic states either via static electric or external optical fields. Here, a pump beam can switch and even coherently amplify a weak laser beam that probes the inherent nonlinearity of a single molecule. Moreover, we gain local control of the molecular resonance frequencies via the dc Stark effect by applying static electric fields on microelectrodes integrated along our chip-compatible nanoguides. Exploiting this tunability allows us to match the resonance frequencies of two molecules that are coherently coupled to the same waveguide mode. All these crucial ingredients, a scalable light-matter interface, high optical densities, external control over the molecular resonance frequencies and their nonlinear response, open up realistic prospects for investigating small, but well-defined networks of quantum emitters coherently coupled via a shared guided mode.

•Jan 1, 2018•2 citations

All-optical switching based on plasmon-induced Enhancement of Index of Refraction

Rakesh Dhama, Ali Panahpour, Tuomas Pihlava +2 more

In quantum optical Enhancement of Index of Refraction (EIR), coherence and quantum interference render the atomic systems to exhibit orders of magnitude higher susceptibilities with vanishing or even negative absorption at their resonances. Here we show the plasmonic analogue of the quantum optical EIR effect in an optical system and further implement this in a linear all-optical switching mechanism. We realize plasmon-induced EIR using a particular plasmonic metasurface consisting of a square array of L-shaped meta-molecules. In contrast to the conventional methods, this approach provides a scheme to modulate the amplitude of incident signals by coherent control of absorption without implementing gain materials or nonlinear processes. Therefore, light is controlled by applying ultra-low intensity at the extreme levels of spatiotemporal localization. In the pursuit of potential applications of linear all-optical switching devices, this scheme may introduce an effective tool for improving the modulation strength of optical modulators and switches through the amplification of input signals at ultra-low power.

Nature Communications•Jun 3, 2022•46 citations

All-optical switching of continuous-variable entanglement in an absorption-suppressed plasmonic nanodimer

Elif Ozturk, Mehmet Gunay, Ramazan Sahin +1 more

A subwavelength quantum-photonic circuit element should simultaneously generate nonclassical light, suppress plasmonic loss, and remain dynamically tunable. We show that an orthogonal plasmonic nanorod dimer can satisfy all three requirements. A phase-locked control polarization induces plasmonic refractive-index enhancement, driving the probe response toward a near-zero-extinction regime while simultaneously tuning the local second-harmonic parametric interaction. The resulting nonlinear plasmonic source operates in an absorption-suppressed regime and enables all-optical control of quantum correlations. We demonstrate switchable logarithmic negativity and single-mode nonclassicality, establishing a route toward actively tunable quantum-plasmonic circuit elements operating well below the diffraction limit.

quant-pharXiv:2606.30315•Jun 30, 2026•0 citations
Strong coupling with single molecules in plasmonic picocavities has emerged as a resource for room-temperature quantum control with nanoscale light. Tip-based nanoprobes can measure the local dynamics of individual molecular picocavities, but the overhead associated with sampling an inhomogeneous picocavity distribution can be challenging for scalability. We propose a macroscopic approach in which an ensemble of molecular picocavities acts as a nonlinear plasmonic metamaterial. Using a quantum optics perspective, we study theoretical performance limits for optical cross-phase modulation in the system, taking into account realistic distributions of picocavity volumes and molecular transition frequencies. The medium nonlinearity is mediated by local strong coupling with the lowest vibronic emission sideband of individual organic chomophores. The local vacua change the refractive index of the medium at the frequency of a weak probe field ωp\omega_pωp​, set to drive the bare zero-phonon absorption band. Refractive index variations Δn/n\Delta n/nΔn/n of a few percent, relative to a molecule-free scenario, are feasible with dilute ensembles. The probe phase evolution can be switched off in the presence of a signal field at a higher frequency ωs\omega_sωs​, for intensities as low as 10 kW/cm2^22. The mechanism for optical switching involves a novel (ωp+ωs\omega_p+\omega_sωp​+ωs​) two-photon absorption channel, assisted by local vacuum fields. Our work paves the way for future studies of plasmonic metamaterials that exploit strong light-molecule interactions, for applications in optical state preparation and control.
We propose to use molecular picocavity ensembles as macroscopic coherent nonlinear optical devices enabled by nanoscale strong coupling. For a generic picocavity model that includes molecular and photonic disorder, we derive theoretical performance bounds for coherent cross-phase modulation signals using weak classical fields of different frequencies. We show that strong coupling of the picocavity vacua with a specific vibronic sideband in the molecular emission spectrum results in a significant variation of the effective refractive index of the metamaterial relative to a molecule-free scenario due to a vacuum-induced Autler–Townes effect. For a realistic molecular disorder model, we demonstrate that cross-phase modulation of optical fields as weak as 10 kW/cm2 is feasible using dilute ensembles of molecular picocavities at room temperature, provided that the confined vacuum is not resonantly driven by the external probe field. Our work paves the way for the development of plasmonic metamaterials that exploit strong coupling for optical state preparation and quantum control.
Molecular ensembles in confined infrared (IR) fields have emerged as a promising platform for condensed-phase cavity QED at room temperature, for the development of scalable architectures for IR quantum optics also at the nanoscale. We develop a Markovian open quantum system approach to study the dynamics of molecular vibrations in infrared nanocavities under femtosecond pulse driving, as implemented in recent nanoprobe spectroscopy experiments with polymer-coated IR gold antennas. We describe the time-domain signatures of the crossover from weak to strong coupling regimes in these nanocavities, provide mechanistic insights on the conditions for implementing coherent phase-space rotations of the nanocavity field using a tip nanoprobe, and discuss the tunable role of molecular anharmonicity as a function of pump power. Our work offers microscopic design strategies for quantum state preparation and control with emitter-nanocavity hybrids using infrared quantum optics.
In this article, we address fluorescence of single molecule inside a plasmonic picocavity by proposing a semi-classical theory via combining the macroscopic quantum electrodynamics theory and the open quantum system theory. To gain insights into the experimental results [Nat. Photonics, 14, 693 (2020)], we have further equipped this theory with the classical electromagnetic simulation of the pico-cavity, formed by single atom decorated silver STM tip and a silver substrate, and the time-dependent density functional theory calculation of zinc phthalocyanine molecule. Our simulations not only reproduce the fluorescence spectrum as measured in the experiment, confirming the influence of extreme field confinement afforded by the picocavity, but also reveal Rabi oscillation dynamics and Mollow triplets spectrum for moderate laser excitation. Thus, our study highlights the possibility of coherently manipulating the molecular state and exploring non-linear optical phenomena with the plasmonic picocavity.
Optical studies of single emitters have become routine for a number of systems ranging from atoms and ions in the gas phase to molecules, color centers and quantum dots in the solid-state. A new direction in experimental quantum optics is to exploit this know-how to assemble well-defined arrangements of optically coupled emitters for investigating quantum many-body physics. However, common approaches via strong focusing or cavity quantum electrodynamics do not scale favorably. We developed a scalable light-matter interface by coupling organic dye molecules to subwavelength dielectric waveguides (nanoguides). Their small effective mode area gives rise to substantial single-emitter coupling efficiencies with expected values up to 35%. By combining high-resolution microscopy with fluorescence excitation and resonance fluorescence spectroscopy, we study the coupled nano-guide-emitter system. Our results demonstrate the versatility of the geometry for reaching high optical densities and yet maintaining the addressability of each single emitter. We show that we can couple several thousand molecules simultaneously and coherently to a single guided mode, while their nearly lifetime-limited resonances are inhomogeneously distributed. The optical response of the coupled nanoguide-emitter system can be controlled by modifying the molecular electronic states either via static electric or external optical fields. Here, a pump beam can switch and even coherently amplify a weak laser beam that probes the inherent nonlinearity of a single molecule. Moreover, we gain local control of the molecular resonance frequencies via the dc Stark effect by applying static electric fields on microelectrodes integrated along our chip-compatible nanoguides. Exploiting this tunability allows us to match the resonance frequencies of two molecules that are coherently coupled to the same waveguide mode. All these crucial ingredients, a scalable light-matter interface, high optical densities, external control over the molecular resonance frequencies and their nonlinear response, open up realistic prospects for investigating small, but well-defined networks of quantum emitters coherently coupled via a shared guided mode.
In quantum optical Enhancement of Index of Refraction (EIR), coherence and quantum interference render the atomic systems to exhibit orders of magnitude higher susceptibilities with vanishing or even negative absorption at their resonances. Here we show the plasmonic analogue of the quantum optical EIR effect in an optical system and further implement this in a linear all-optical switching mechanism. We realize plasmon-induced EIR using a particular plasmonic metasurface consisting of a square array of L-shaped meta-molecules. In contrast to the conventional methods, this approach provides a scheme to modulate the amplitude of incident signals by coherent control of absorption without implementing gain materials or nonlinear processes. Therefore, light is controlled by applying ultra-low intensity at the extreme levels of spatiotemporal localization. In the pursuit of potential applications of linear all-optical switching devices, this scheme may introduce an effective tool for improving the modulation strength of optical modulators and switches through the amplification of input signals at ultra-low power.
A subwavelength quantum-photonic circuit element should simultaneously generate nonclassical light, suppress plasmonic loss, and remain dynamically tunable. We show that an orthogonal plasmonic nanorod dimer can satisfy all three requirements. A phase-locked control polarization induces plasmonic refractive-index enhancement, driving the probe response toward a near-zero-extinction regime while simultaneously tuning the local second-harmonic parametric interaction. The resulting nonlinear plasmonic source operates in an absorption-suppressed regime and enables all-optical control of quantum correlations. We demonstrate switchable logarithmic negativity and single-mode nonclassicality, establishing a route toward actively tunable quantum-plasmonic circuit elements operating well below the diffraction limit.