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Networking Molecular Quantum Emitters on a Single Chain : From Single to Cooperative Emitters
Authors:
Jean-Baptiste Marceau,
Juliette Le Balle,
Christel Poujol,
Frédéric Fossard,
Annick Loiseau,
Gaëlle Recher,
Etienne Gaufrès
Abstract:
Engineering light-matter interactions between multiple free-space quantum emitters is a central challenge for scalable quantum photonic technologies. In particular, accessing regimes of coherent emitter-emitter interactions, where several emitters are coupled through a shared electromagnetic environment, is essential for coherent emission and quantum functionalities. Such interactions require prec…
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Engineering light-matter interactions between multiple free-space quantum emitters is a central challenge for scalable quantum photonic technologies. In particular, accessing regimes of coherent emitter-emitter interactions, where several emitters are coupled through a shared electromagnetic environment, is essential for coherent emission and quantum functionalities. Such interactions require precise control over emitter separation and stabilization at sub-wavelength distances, a level of spatial organization that remains extremely difficult to achieve at the molecular scale in solid-state systems. Here we introduce Encoded Quantum Chains (EQC), a one-dimensional architecture in which cooperative radiative behaviour is programmed through spatial encoding of identical molecular emitters. Organic emitters and inert spacer molecules are co-encapsulated inside dielectric boron nitride nanotubes (BNNTs), enabling statistical control of intermolecular spacing from nanometres to micrometres while enforcing dipole alignment and one-dimensional confinement. Time-resolved fluorescence under ambient conditions reveals accelerated radiative decay, enhanced emission rates per emitter, and the emergence of non-mono-exponential dynamics as spacing falls below the optical wavelength, consistent with cooperative radiative states in one dimension. Bundling of EQCs enables coupling between emitters in neighbouring BNNTs, driving a dimensional crossover toward higher-dimensional delocalisation of the excitation. This modular building-block approach provides a scalable route to engineer light-matter interactions and many-body optical phenomena in confined molecular systems, opening new opportunities for distributed single-photon sources, programmable quantum emitters, and photonic architectures for quantum technologies.
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Submitted 1 March, 2026;
originally announced March 2026.
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Straightforward Method to Orient Black Phosphorus from Bulk to Thin Layers using a Standard Green Laser
Authors:
Etienne Carré,
Frédéric Fossard,
Jean-Sébastien Mérot,
Denis Boivin,
Nicolas Horezan,
Victor Zatko,
Florian Godel,
Bruno Dlubak,
Marie-Blandine Martin,
Pierre Seneor,
Etienne Gaufres,
Julien Barjon,
Annick Loiseau,
Ingrid Stenger
Abstract:
The crystallographic orientation of anisotropic 2D materials plays a crucial role in their physical properties and device performance. However, standard orientation techniques such as transmission electron microscopy (TEM) or X-ray diffraction (XRD) can be complex and less accessible for routine characterization. In this study, we investigate the orientation of black phosphorus (BP) from bulk crys…
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The crystallographic orientation of anisotropic 2D materials plays a crucial role in their physical properties and device performance. However, standard orientation techniques such as transmission electron microscopy (TEM) or X-ray diffraction (XRD) can be complex and less accessible for routine characterization. In this study, we investigate the orientation of black phosphorus (BP) from bulk crystals to thin layers using angle-resolved polarized Raman spectroscopy (ARPRS) with a single-wavelength (514 nm) Raman setup. By incorporating thickness-dependent interference effects and anisotropic optical indices, this approach provides a reliable framework for orientation determination across different BP thicknesses. The method is validated through direct orientation measurements using TEM and Electron Backscattering Diffraction (EBSD), confirming its applicability to both thick and ultrathin samples. Given its simplicity and compatibility with widely available Raman setups, this approach offers a practical solution for characterizing BP orientation without requiring advanced structural characterization techniques.
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Submitted 6 August, 2025;
originally announced August 2025.
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Forming 1D Periodic J-aggregates by Mechanical Bending of BNNTs: Evidence of Activated Molecular Diffusion
Authors:
J. -B. Marceau,
D. -M Ta,
A. Aguilar,
A. Loiseau,
R. Martel,
P. Bon,
R. Voituriez,
G. Recher,
E. Gaufrès
Abstract:
Driving molecular assembly into micrometer-scale patterns is key for defining advanced materials of interest in various fields, including life sciences, photovoltaics, and quantum photonics. However, the driving process competes with other forces, such as Brownian motion, ripening phenomena, capillary forces, and non-specific adsorption. Here we report on a guided diffusion mechanism of luminescen…
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Driving molecular assembly into micrometer-scale patterns is key for defining advanced materials of interest in various fields, including life sciences, photovoltaics, and quantum photonics. However, the driving process competes with other forces, such as Brownian motion, ripening phenomena, capillary forces, and non-specific adsorption. Here we report on a guided diffusion mechanism of luminescent dye molecules encapsulated inside boron nitride nanotubes (BNNTs). Correlative measurements between BNNT bending and molecular position along the BNNT axis reveal an efficient and long-range migration of dyes from curved to straight regions of the nanotube. This curvature activated diffusion forms clusters of bright J-aggregates in periodic patterns of well-defined spacing and length. A phenomenological model of guided molecular transport in bended BNNTs is used to describe this directed 1D diffusion inside BNNT. It is shown to accurately predict the position and morphologies of a J-aggregate as a function of nanotube length. Coupling topological stimuli to 1D molecular diffusion at the nanoscale is here presented as an interesting tool capable of reconfiguring various emissive patterns of functional molecules at the mesoscopic scale.
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Submitted 27 February, 2024;
originally announced February 2024.
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Quantum well confinement and competitive radiative pathways in the luminescence of black phosphorus layers
Authors:
Etienne Carré,
Lorenzo Sponza,
Alain Lusson,
Ingrid Stenger,
Sébastien Roux,
Victor Zatko,
Bruno Dlubak,
Pierre Seneor,
Etienne Gaufrès,
Annick Loiseau,
Julien Barjon
Abstract:
Black phosphorus (BP) stands out from other 2D materials by the wide amplitude of the band-gap energy (Delta(Eg)) that sweeps an optical window from Visible (VIS) to Infrared (IR) wavelengths, depending on the layer thickness. This singularity made the optical and excitonic properties of BP difficult to map. Specifically, the literature lacks in presenting experimental and theoretical data on the…
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Black phosphorus (BP) stands out from other 2D materials by the wide amplitude of the band-gap energy (Delta(Eg)) that sweeps an optical window from Visible (VIS) to Infrared (IR) wavelengths, depending on the layer thickness. This singularity made the optical and excitonic properties of BP difficult to map. Specifically, the literature lacks in presenting experimental and theoretical data on the optical properties of BP on an extended thickness range. Here we report the study of an ensemble of photoluminescence spectra from 79 passivated BP flakes recorded at 4 K with thicknesses ranging from 4 nm to 700 nm, obtained by mechanical exfoliation. We observe that the exfoliation steps induce additional defects states that compete the radiative recombination from bound excitons observed in the crystal. We also show that the evolution of the photoluminescence energy versus thickness follows a quantum well confinement model appreciable from a thickness predicted and probed at 25 nm. The BP slabs placed in different 2D heterostructures show that the emission energy is not significantly modulated by the dielectric environment. Introduction Confinement effects
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Submitted 2 December, 2022;
originally announced December 2022.
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Highly Polarized Light Emission from 6T@BNNT Nanohybrids
Authors:
A. Badon,
C. Allard,
F. Fossard,
A. Loiseau,
L. Cognet,
E. Flahaut,
N. Izard,
R. Martel,
E. Gaufrès
Abstract:
The polarized fluorescence emission of organic fluorophores has been extensively studied in photonics and is increasingly exploited in single molecule scale bio-imaging. Expanding the polarization properties of compact molecular assemblies is, however, extremely challenging due to depolarization and quenching effects associated with the self-aggregation of molecules into the sub-nanometer scale. H…
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The polarized fluorescence emission of organic fluorophores has been extensively studied in photonics and is increasingly exploited in single molecule scale bio-imaging. Expanding the polarization properties of compact molecular assemblies is, however, extremely challenging due to depolarization and quenching effects associated with the self-aggregation of molecules into the sub-nanometer scale. Here we demonstrate that Boron Nitride Nanotubes (BNNTs) can act as a 1D host-template for the alignment of encapsulated a-sexithiophene (6T) inside BNNTs, leading to an optically active 6T@BNNT nanohybrid. We show that the fluorescence from the nanohybrid is strongly polarized with extinction ratios as high as 700 at room temperature. A statistical analysis of the 6T orientation inside BNNTs with inner diameter up to 1.5 nm shows that at least 80% of the encapsulated 6Ts exhibit a maximum deviation angle of less than 10° with respect to the BNNT axis. Despite a competition between molecule-molecule and molecule-BNNT adsorption in larger BNNTs, our results also show that more than 80% of the molecules display a preferential orientation along the BNNT axis with a deviation angle below 45°.
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Submitted 5 January, 2021;
originally announced January 2021.
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Excitons in bulk black phosphorus evidenced by photoluminescence at low temperature
Authors:
Etienne Carré,
Lorenzo Sponza,
Alain Lusson,
Ingrid Stenger,
Etienne Gaufrès,
Annick Loiseau,
Julien Barjon
Abstract:
Atomic layers of Black Phosphorus (BP) present unique opto-electronic properties dominated by a direct tunable bandgap in a wide spectral range from visible to mid-infrared. In this work, we investigate the infrared photoluminescence of BP single crystals at very low temperature. Near-bandedge recombinations are observed at 2 K, including dominant excitonic transitions at 0.276 eV and a weaker one…
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Atomic layers of Black Phosphorus (BP) present unique opto-electronic properties dominated by a direct tunable bandgap in a wide spectral range from visible to mid-infrared. In this work, we investigate the infrared photoluminescence of BP single crystals at very low temperature. Near-bandedge recombinations are observed at 2 K, including dominant excitonic transitions at 0.276 eV and a weaker one at 0.278 eV. The free-exciton binding energy is calculated with an anisotropic Wannier-Mott model and found equal to 9.1 meV. On the contrary, the PL intensity quenching of the 0.276 eV peak at high temperature is found with a much smaller activation energy, attributed to the localization of free excitons on a shallow impurity. This analysis leads us to attribute respectively the 0.276 eV and 0.278 eV PL lines to bound excitons and free excitons in BP. As a result, the value of bulk BP bandgap is refined to 0.287 eV at 2K.
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Submitted 29 October, 2020;
originally announced October 2020.
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Electroabsorption study of index-defined semiconducting carbon nanotubes
Authors:
Nicolas Izard,
Etienne Gaufrès,
Xavier Le Roux,
Saïd Kazaoui,
Yoichi Murakami,
Delphine Marris-Morini,
Eric Cassan,
Shigeo Maruyama,
Laurent Vivien
Abstract:
Electroabsorption spectroscopy of well-identified index-defined semiconducting carbon nanotubes is reported. The measurement of high definition electroabsorption spectra allows direct indexation with unique nanotube chirality. Results show that at least for a limited range of diameters, electroabsorption is directly proportional to the exciton binding energy of nanotubes. Electroabsorption is a po…
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Electroabsorption spectroscopy of well-identified index-defined semiconducting carbon nanotubes is reported. The measurement of high definition electroabsorption spectra allows direct indexation with unique nanotube chirality. Results show that at least for a limited range of diameters, electroabsorption is directly proportional to the exciton binding energy of nanotubes. Electroabsorption is a powerful technique which directly probes into carbon nanotube excitonic states, and may become a useful tool for in situ study of excitons in future nanotube-based photonic devices such as electroabsorption modulators.
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Submitted 5 August, 2015;
originally announced August 2015.
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Two-Dimensional Magnetotransport in a Black Phosphorus Naked Quantum Well
Authors:
V. Tayari,
N. Hemsworth,
I. Fakih,
A. Favron,
E. Gaufrès,
G. Gervais,
R. Martel,
T. Szkopek
Abstract:
Black phosphorus (bP) is the second known elemental allotrope with a layered crystal structure that can be mechanically exfoliated down to atomic layer thickness. We have fabricated bP naked quantum wells in a back-gated field effect transistor geometry with bP thicknesses ranging from $6\pm1$ nm to $47\pm1$ nm. Using an encapsulating polymer superstrate, we have suppressed bP oxidation and have o…
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Black phosphorus (bP) is the second known elemental allotrope with a layered crystal structure that can be mechanically exfoliated down to atomic layer thickness. We have fabricated bP naked quantum wells in a back-gated field effect transistor geometry with bP thicknesses ranging from $6\pm1$ nm to $47\pm1$ nm. Using an encapsulating polymer superstrate, we have suppressed bP oxidation and have observed field effect mobilities up to 600 cm$^2$/Vs and on/off current ratios exceeding $10^5$. Importantly, Shubnikov-de Haas (SdH) oscillations observed in magnetotransport measurements up to 35 T reveal the presence of a 2-D hole gas with Schrödinger fermion character in an accumulation layer at the bP/oxide interface. Our work demonstrates that 2-D electronic structure and 2-D atomic structure are independent. 2-D carrier confinement can be achieved in layered semiconducting materials without necessarily approaching atomic layer thickness, advantageous for materials that become increasingly reactive in the few-layer limit such as bP.
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Submitted 30 November, 2014;
originally announced December 2014.
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Exfoliating pristine black phosphorus down to the monolayer: photo-oxidation and electronic confinement effects
Authors:
A. Favron,
E. Gaufrès,
F. Fossard,
P. L. Lévesque,
A-L. Phaneuf-L'Heureux,
N. Y-W. Tang,
A. Loiseau,
R. Leonelli,
S. Francoeur,
R. Martel
Abstract:
Thin layers of black phosphorus have recently raised interest for their two-dimensional (2D) semiconducting properties, such as tunable direct bandgap and high carrier mobilities. This lamellar crystal of P atoms stacked together by weak van der Waals forces can be exfoliated down to the stratophosphane monolayer (also called phosphorene) using procedures similar to those used for graphene. Proper…
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Thin layers of black phosphorus have recently raised interest for their two-dimensional (2D) semiconducting properties, such as tunable direct bandgap and high carrier mobilities. This lamellar crystal of P atoms stacked together by weak van der Waals forces can be exfoliated down to the stratophosphane monolayer (also called phosphorene) using procedures similar to those used for graphene. Properties of this 2D material are however challenging to probe due to a fast and ubiquitous degradation upon exposure to ambient conditions. Herein, we investigate the crystal degradation using in-situ Raman and transmission electron spectroscopies and highlight a process involving a photo-induced oxidation reaction with adsorbed oxygen in water. The experimental conditions to prepare and preserve mono-, bi- and multilayers of stratophosphane in their pristine states were determined. Study on these 2D layers provides new insights on the effect of confinement on the chemical reactivity and the vibrational modes of black phosphorus.
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Submitted 21 August, 2014; v1 submitted 2 August, 2014;
originally announced August 2014.
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Phonon-Induced Transparency in Functionalized Single Layer Graphene
Authors:
Bruno Rousseau,
François Lapointe,
Minh Nguyen,
Maxime Biron,
Etienne Gaufrès,
Saman Choubak,
Zheng Han,
Vincent Bouchiat,
Patrick Desjardins,
Michel Côté,
Richard Martel
Abstract:
Herein, intervalley scattering is exploited to account for anomalous antiresonances in the infrared spectra of doped and disordered single layer graphene. We present infrared spectroscopy measurements of graphene grafted with iodophenyl moieties in both reflection microscopy and transmission configurations. Asymmetric transparency windows at energies corresponding to phonon modes near the Γ and K…
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Herein, intervalley scattering is exploited to account for anomalous antiresonances in the infrared spectra of doped and disordered single layer graphene. We present infrared spectroscopy measurements of graphene grafted with iodophenyl moieties in both reflection microscopy and transmission configurations. Asymmetric transparency windows at energies corresponding to phonon modes near the Γ and K points are observed, in contrast to the featureless spectrum of pristine graphene. These asymmetric antiresonances are demonstrated to vary as a function of the chemical potential. We propose a model which involves coherent intraband scattering with defects and phonons, thus relaxing the optical selection rule forbidding access to ${\bf q} \neq$ Γ phonons. This interpretation of the new phenomenon is supported by our numerical simulations that reproduce the experimental features.
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Submitted 18 August, 2015; v1 submitted 30 July, 2014;
originally announced July 2014.
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Fano Resonances in Mid-Infrared Spectra of Single-Walled Carbon Nanotubes
Authors:
François Lapointe,
Étienne Gaufrés,
Isabelle Tremblay,
Nathalie Y-Wa Tang,
Patrick Desjardins,
Richard Martel
Abstract:
This work revisits the physics giving rise to the carbon nanotubes phonon bands in the mid- infrared. Our measurements of doped and undoped samples of single-walled carbon nanotubes in Fourier transform infrared spectroscopy show that the phonon bands exhibit an asymmetric lineshape and that their effective cross-section is enhanced upon doping. We relate these observations to electron-phonon coup…
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This work revisits the physics giving rise to the carbon nanotubes phonon bands in the mid- infrared. Our measurements of doped and undoped samples of single-walled carbon nanotubes in Fourier transform infrared spectroscopy show that the phonon bands exhibit an asymmetric lineshape and that their effective cross-section is enhanced upon doping. We relate these observations to electron-phonon coupling or, more specifically, to a Fano resonance phenomenon. We note that only the dopant-induced intraband continuum couples to the phonon modes and that defects induced in the sidewall increase the resonance probabilities.
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Submitted 14 March, 2012;
originally announced March 2012.
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Optical Gain in Carbon Nanotubes
Authors:
Etienne Gaufrès,
Nicolas Izard,
Xavier Le Roux,
Delphine Marris-Morini,
Saïd Kazaoui,
Eric Cassan,
Laurent Vivien
Abstract:
Semiconducting single-wall carbon nanotubes (s-SWNTs) have proved to be promising material for nanophotonics and optoelectronics. Due to the possibility of tuning their direct band gap and controlling excitonic recombinations in the near-infrared wavelength range, s-SWNT can be used as efficient light emitters. We report the first experimental demonstration of room temperature intrinsic optical ga…
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Semiconducting single-wall carbon nanotubes (s-SWNTs) have proved to be promising material for nanophotonics and optoelectronics. Due to the possibility of tuning their direct band gap and controlling excitonic recombinations in the near-infrared wavelength range, s-SWNT can be used as efficient light emitters. We report the first experimental demonstration of room temperature intrinsic optical gain as high as 190 cm-1 at a wavelength of 1.3 μm in a thin film doped with s-SWNT. These results constitute a significant milestone toward the development of laser sources based on carbon nanotubes for future high performance integrated circuits.
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Submitted 28 November, 2010;
originally announced November 2010.
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Optical microcavity with semiconducting single-wall carbon nanotubes
Authors:
Etienne Gaufrès,
Nicolas Izard,
Xavier Le Roux,
Saïd Kazaoui,
Delphine Marris-Morini,
Eric Cassan,
Laurent Vivien
Abstract:
We report studies of optical Fabry-Perot microcavities based on semiconducting single-wall carbon nanotubes with a quality factor of 160. We experimentally demonstrate a huge photoluminescence signal enhancement by a factor of 30 in comparison with the identical film and by a factor of 180 if compared with a thin film containing non-purified (8,7) nanotubes. Futhermore, the spectral full-width at…
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We report studies of optical Fabry-Perot microcavities based on semiconducting single-wall carbon nanotubes with a quality factor of 160. We experimentally demonstrate a huge photoluminescence signal enhancement by a factor of 30 in comparison with the identical film and by a factor of 180 if compared with a thin film containing non-purified (8,7) nanotubes. Futhermore, the spectral full-width at half-maximum of the photo-induced emission is reduced down to 8 nm with very good directivity at a wavelength of about 1.3 $μ$m. Such results prove the great potential of carbon nanotubes for photonic applications.
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Submitted 25 October, 2010;
originally announced October 2010.
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Enhancement of semiconducting single-wall carbon nanotubes photoluminescence
Authors:
Etienne Gaufrès,
Nicolas Izard,
Laurent Vivien,
Saïd Kazaoui,
Delphine Marris-Morini,
Eric Cassan
Abstract:
Photoluminescence properties of semiconducting single wall carbon nanotubes (s-SWNT) thin films with different metallic single wall carbon nanotubes (m-SWNT) concentrations are reported. s-SWNT purified samples are obtained by polymer assisted selective extraction. We show that a few m-SWNT in the sample generates a drastic quenching of the emission. Therefore, highly purified s-SWNT films are a…
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Photoluminescence properties of semiconducting single wall carbon nanotubes (s-SWNT) thin films with different metallic single wall carbon nanotubes (m-SWNT) concentrations are reported. s-SWNT purified samples are obtained by polymer assisted selective extraction. We show that a few m-SWNT in the sample generates a drastic quenching of the emission. Therefore, highly purified s-SWNT films are a strongly luminescent material and a good candidate for future applications in photonics, such as near infrared emitters, modulators and detectors.
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Submitted 6 January, 2010;
originally announced January 2010.