946 research outputs found
Anti Stokes Thermometry of Plasmonic Nanoparticle Arrays
Metallic nanoparticles possess strong photothermal responses, especially when illuminated as ensembles due to collective effects. However, accurately quantifying the temperature increase remains a significant challenge, impeding progress in several applications. Anti Stokes thermometry offers a promising solution by enabling direct and non-invasive temperature measurements of the metal without the need for labeling or prior calibration. While Anti Stokes thermometry is successfully applied to individual nanoparticles, its potential to study light-to-heat conversion with plasmonic ensembles remains unexplored. In this study, the theoretical framework and the conditions that must be fulfilled for applying Anti Stokes thermometry to ensembles of nanoparticles are discussed. Then, this technique is implemented to measure the light-induced heating of square arrays of Au nanodisks. The obtained temperature measurements are validated using wavefront microscopy, demonstrating excellent agreement between the two thermometry methods. These results showcase the extension of Anti Stokes thermometry to plasmonic ensembles, highlighting its potential for implementation in the diverse photothermal applications involving these systems
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3D-nanoprinted on-chip antiresonant waveguide with hollow core and microgaps for integrated optofluidic spectroscopy
Here, we unlock the properties of the recently introduced on-chip hollow-core microgap waveguide in the context of optofluidics which allows for intense light-water interaction over long lengths with fast response times. The nanoprinted waveguide operates by the antiresonance effect in the visible and near-infrared domain and includes a hollow core with defined gaps every 176 µm. The spectroscopic capabilities are demonstrated by various absorption-related experiments, showing that the Beer-Lambert law can be applied without any modification. In addition to revealing key performance parameters, time-resolved experiments showed a decisive improvement in diffusion times resulting from the lateral access provided by the microgaps. Overall, the microgap waveguide represents a pathway for on-chip spectroscopy in aqueous environments
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Coherent interaction of atoms with a beam of light confined in a light cage
Controlling coherent interaction between optical fields and quantum systems in scalable, integrated platforms is essential for quantum technologies. Miniaturised, warm alkali-vapour cells integrated with on-chip photonic devices represent an attractive system, in particular for delay or storage of a single-photon quantum state. Hollow-core fibres or planar waveguides are widely used to confine light over long distances enhancing light-matter interaction in atomic-vapour cells. However, they suffer from inefficient filling times, enhanced dephasing for atoms near the surfaces, and limited light-matter overlap. We report here on the observation of modified electromagnetically induced transparency for a non-diffractive beam of light in an on-chip, laterally-accessible hollow-core light cage. Atomic layer deposition of an alumina nanofilm onto the light-cage structure was utilised to precisely tune the high-transmission spectral region of the light-cage mode to the operation wavelength of the atomic transition, while additionally protecting the polymer against the corrosive alkali vapour. The experiments show strong, coherent light-matter coupling over lengths substantially exceeding the Rayleigh range. Additionally, the stable non-degrading performance and extreme versatility of the light cage provide an excellent basis for a manifold of quantum-storage and quantum-nonlinear applications, highlighting it as a compelling candidate for all-on-chip, integrable, low-cost, vapour-based photon delay
Impact of bimetallic interface design on heat generation in plasmonic Au/Pd nanostructures studied by single-particle thermometry
Localized surface plasmons are lossy and generate heat. However, accurate measurement of the temperature of metallic nanoparticles under illumination remains an open challenge, creating difficulties in the interpretation of results across plasmonic applications. Particularly, there is a quest for understanding the role of temperature in plasmon-assisted catalysis. Bimetallic nanoparticles combining plasmonic with catalytic metals are raising increasing interest in artificial photosynthesis and the production of solar fuels. Here, we perform single-particle thermometry measurements to investigate the link between morphology and light-to-heat conversion of colloidal Au/Pd nanoparticles with two different configurations: core–shell and core-satellite. It is observed that the inclusion of Pd as a shell strongly reduces the photothermal response in comparison to the bare cores, while the inclusion of Pd as satellites keeps photothermal properties almost unaffected. These results contribute to a better understanding of energy conversion processes in plasmon-assisted catalysis.Fil: Gargiulo, Julian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; Argentina. Universidad Nacional de San Martin. Instituto de Nanosistemas; ArgentinaFil: Herran, Matias. Ludwig Maximilians Universitat; AlemaniaFil: Violi, Ianina Lucila. Universidad Nacional de San Martin. Instituto de Nanosistemas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; ArgentinaFil: Sousa Castillo, Ana. Ludwig Maximilians Universitat; AlemaniaFil: Martínez, Luciana Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; ArgentinaFil: Ezendam, Simone. Ludwig Maximilians Universitat; AlemaniaFil: Barella, Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; ArgentinaFil: Giesler, Helene. Universitat Essen; AlemaniaFil: Grzeschik, Roland. Universitat Essen; AlemaniaFil: Schlücker, Sebastian. Universitat Essen; AlemaniaFil: Maier, Stefan A.. Monash University; Australia. Imperial College London; Reino Unido. Ludwig Maximilians Universitat; AlemaniaFil: Stefani, Fernando Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; ArgentinaFil: Cortés, Emiliano. Ludwig Maximilians Universitat; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; Argentin
In situ photothermal response of single gold nanoparticles through hyperspectral imaging anti-stokes thermometry
Several fields of applications require a reliable characterization of the photothermal response and heat dissipation of nanoscopic systems, which remains a challenging task for both modeling and experimental measurements. Here, we present an implementation of anti-Stokes thermometry that enables the in situ photothermal characterization of individual nanoparticles (NPs) from a single hyperspectral photoluminescence confocal image. The method is label-free, potentially applicable to any NP with detectable anti-Stokes emission, and does not require any prior information about the NP itself or the surrounding media. With it, we first studied the photothermal response of spherical gold NPs of different sizes on glass substrates, immersed in water, and found that heat dissipation is mainly dominated by the water for NPs larger than 50 nm. Then, the role of the substrate was studied by comparing the photothermal response of 80 nm gold NPs on glass with sapphire and graphene, two materials with high thermal conductivity. For a given irradiance level, the NPs reach temperatures 18% lower on sapphire and 24% higher on graphene than on bare glass. The fact that the presence of a highly conductive material such as graphene leads to a poorer thermal dissipation demonstrates that interfacial thermal resistances play a very significant role in nanoscopic systems and emphasize the need for in situ experimental thermometry techniques. The developed method will allow addressing several open questions about the role of temperature in plasmon-assisted applications, especially ones where NPs of arbitrary shapes are present in complex matrixes and environments.Fil: Barella, Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; ArgentinaFil: Violi, Ianina Lucila. Universidad Nacional de San Martin. Instituto de Nanosistemas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; ArgentinaFil: Gargiulo, Julian. Ludwig Maximilians Universitat; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Martínez, Luciana Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; ArgentinaFil: Goschin, Florian. Ludwig Maximilians Universitat; AlemaniaFil: Guglielmotti, Victoria. Universidad Nacional de San Martin. Instituto de Nanosistemas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pallarola, Diego Andres. Universidad Nacional de San Martin. Instituto de Nanosistemas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Schlücker, Sebastian. Universitat Essen; AlemaniaFil: Pilo Pais, Mauricio. University Of Fribourg; SuizaFil: Acuna, Guillermo P.. University Of Fribourg; SuizaFil: Maier, Stefan A.. Ludwig Maximilians Universitat; Alemania. Imperial College London; Reino UnidoFil: Cortés, Emiliano. Ludwig Maximilians Universitat; AlemaniaFil: Stefani, Fernando Daniel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; Argentin
Challenges on Optical Printing of Colloidal Nanoparticles
While colloidal chemistry provides ways to obtain a great variety of nanoparticles with different shapes, sizes, material composition, and surface functions, their controlled deposition and combination on arbitrary positions of substrates remains a considerable challenge. Over the last ten years, optical printing arose as a versatile method to achieve this purpose for different kinds of nanoparticles. In this article, we review the state of the art of optical printing of single nanoparticles and discuss its strengths, limitations, and future perspectives, by focusing on four main challenges: printing accuracy, resolution, selectivity, and nanoparticles photostability.Fil: Violi, Ianina Lucila. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; Argentina. Universidad Nacional de San Martin. Instituto de Nanosistemas; ArgentinaFil: Martínez, Luciana Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; ArgentinaFil: Barella, Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; ArgentinaFil: Zaza, María Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; ArgentinaFil: Chvátal, Lukás. Czech Academy of Sciences; República ChecaFil: Zemánek, Pavel. Czech Academy of Sciences; República ChecaFil: Gutierrez, Marina Veronica. Universidad Tecnológica Nacional. Facultad Regional Delta; ArgentinaFil: Paredes, María Yanela. Universidad Tecnológica Nacional. Facultad Regional Delta; ArgentinaFil: Scarpettini, Alberto Franco. Universidad Tecnológica Nacional. Facultad Regional Delta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Olmos Trigo, Jorge. Donostia International Physic Center; EspañaFil: Pais, Valeria Rocío. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; ArgentinaFil: Díaz Nóblega, Iván Agustín. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; ArgentinaFil: Cortés, Emiliano. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ludwig Maximilians Universitat. Katholisch - Theologische Fakultat; AlemaniaFil: Sáenz, Juan José. Donostia International Physic Center; EspañaFil: Bragas, Andrea Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; ArgentinaFil: Gargiulo, Julian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; Argentina. Ludwig Maximilians Universitat. Katholisch - Theologische Fakultat; AlemaniaFil: Stefani, Fernando Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentin
Understanding and reducing photothermal forces for the fabrication of Au nanoparticle dimers by optical printing
Optical printing holds great potential to enable the use of the vast variety of colloidal nanoparticles (NPs) in nano- and microdevices and circuits. By means of optical forces, it enables the direct assembly of NPs, one by one, onto specific positions of solid surfaces with great flexibility of pattern design and no need of previous surface patterning.
However, for unclear causes it was not possible to print identical NPs closer to each other than 300 nm. Here, we show that the repulsion restricting the optical printing of close by NPs arises from light absorption by the printed NPs and subsequent local heating. By optimizing heat dissipation, it is possible to reduce the minimum separation between NPs. Using a reduced graphene oxide layer on a sapphire substrate, we demonstrate for the first time the optical printing of Au-Au NP dimers. Modeling the experiments considering optical, thermophoretic, and thermo-osmotic forces we obtain a detailed understanding and a clear pathway for the optical printing fabrication of complex nano structures and circuits based on connected colloidal NPs.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada
Cosmic CARNage II: the evolution of the galaxy stellar mass function in observations and galaxy formation models
We present a comparison of the observed evolving galaxy stellar mass functions with the predictions of eight semi-analytic models and one halo occupation distribution model. While most models are able to fit the data at low redshift, some of them struggle to simultaneously fit observations at high redshift. We separate the galaxies into 'passive' and 'star-forming' classes and find that several of the models produce too many low-mass star-forming galaxies at high redshift compared to observations, in some cases by nearly a factor of 10 in the redshift range 2.5 < z < 3.0. We also find important differences in the implied mass of the dark matter haloes the galaxies inhabit, by comparing with halo masses inferred from observations. Galaxies at high redshift in the models are in lower mass haloes than suggested by observations, and the star formation efficiency in low-mass haloes is higher than observed. We conclude that many of the models require a physical prescription that acts to dissociate the growth of low-mass galaxies from the growth of their dark matter haloes at high redshift.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat
Cosmic CARNage II: the evolution of the galaxy stellar mass function in observations and galaxy formation models
We present a comparison of the observed evolving galaxy stellar mass functions with the predictions of eight semi-analytic models and one halo occupation distribution model. While most models are able to fit the data at low redshift, some of them struggle to simultaneously fit observations at high redshift. We separate the galaxies into 'passive' and 'star-forming' classes and find that several of the models produce too many low-mass star-forming galaxies at high redshift compared to observations, in some cases by nearly a factor of 10 in the redshift range 2.5 < z < 3.0. We also find important differences in the implied mass of the dark matter haloes the galaxies inhabit, by comparing with halo masses inferred from observations. Galaxies at high redshift in the models are in lower mass haloes than suggested by observations, and the star formation efficiency in low-mass haloes is higher than observed. We conclude that many of the models require a physical prescription that acts to dissociate the growth of low-mass galaxies from the growth of their dark matter haloes at high redshift.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat
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