scholarly journals On the Fly” Characterization of YbIII:ErIII Co-Doped Upconversion Nanoparticle Nonlinear Optical Response from Single-Particle Trajectories

2021 ◽  
Author(s):  
Isabela Cavalcante ◽  
María Claudia Marchi ◽  
Fernando Sigoli ◽  
Paulo Cesar de Sousa Filho ◽  
Beatriz C. Barja ◽  
...  
Keyword(s):  
Single Particle ◽  
Nonlinear Optical ◽  
Near Infrared ◽  
Stochastic Dynamics ◽  
Optical Power ◽  
Spectroscopic Characterization ◽  
Structure Property ◽  
Individual Nanoparticles ◽  
Co Doped

<p> Spectroscopic characterization of individual nanoparticles is essential for understanding their structure-property relationship and for applications. Upconversion nanoparticles (UCNPs) in condensed phases can undergo both nonlinear optical and stochastic dynamics when interacting with near-infrared sources. By integrating optical trapping microspectroscopy, stochastic dynamics and light-matter interactions experiments and simulations, in the present work we study how individual trajectories of YbIII:ErIII co-doped UCNPs can be used to perform “on the fly” characterization of their nonlinear optical power-law response upon near-infrared excitation. We illustrate the methodology in the case of freely diffusing and optically trapped UCNPs as well as with particles bound to the substrate. The approach presented in this work can be applied to UCNPs with varying composition and morphological features, particularly in single-particle studies.</p>

scholarly journals On the Fly” Characterization of YbIII:ErIII Co-Doped Upconversion Nanoparticle Nonlinear Optical Response from Single-Particle Trajectories

2021 ◽  
Author(s):  
Isabela Cavalcante ◽  
María Claudia Marchi ◽  
Fernando Sigoli ◽  
Paulo Cesar de Sousa Filho ◽  
Beatriz C. Barja ◽  
...  
Keyword(s):  
Single Particle ◽  
Nonlinear Optical ◽  
Near Infrared ◽  
Stochastic Dynamics ◽  
Optical Power ◽  
Spectroscopic Characterization ◽  
Structure Property ◽  
Individual Nanoparticles ◽  
Co Doped

<p> Spectroscopic characterization of individual nanoparticles is essential for understanding their structure-property relationship and for applications. Upconversion nanoparticles (UCNPs) in condensed phases can undergo both nonlinear optical and stochastic dynamics when interacting with near-infrared sources. By integrating optical trapping microspectroscopy, stochastic dynamics and light-matter interactions experiments and simulations, in the present work we study how individual trajectories of YbIII:ErIII co-doped UCNPs can be used to perform “on the fly” characterization of their nonlinear optical power-law response upon near-infrared excitation. We illustrate the methodology in the case of freely diffusing and optically trapped UCNPs as well as with particles bound to the substrate. The approach presented in this work can be applied to UCNPs with varying composition and morphological features, particularly in single-particle studies.</p>

Enhanced Near-Infrared Emission from Holmium–Ytterbium Co-Doped Phosphate Glasses Containing Silver Nanoparticles

2014 ◽  
Vol 68 (11) ◽  
pp. 1247-1253 ◽  
Author(s):  
Miguel A. Vallejo Hernandez ◽  
M. Alejandrina Martínez Gámez ◽  
José L. Lucio Martínez ◽  
Alexander V. Kir'yanov
Keyword(s):  
Silver Nanoparticles ◽  
Near Infrared ◽  
Spectroscopic Characterization ◽  
Resonant Absorption ◽  
Infrared Emission ◽  
Phosphate Glasses ◽  
Transmission Electron ◽  
Near Infrared Emission ◽  
Co Doped

The fabrication and spectroscopic characterization of Ho3+ and Yb3+ co-doped phosphate glasses, also containing silver nanoparticles (SNPs), is reported. The nucleation and formation of nanoparticle structures in the samples are confirmed using transmission electron microscopy analyses. It is found that the Ho3+-Yb3+-SNP phosphate glasses exhibit an enhancement of both the resonant-absorption and the fluorescence properties when the SNP concentration is increased.

Bayesian Spectroscopic Characterization of Directly Imaged Planets and Brown Dwarfs and Implications for Ultracool Model Atmospheres

2021 ◽  
Author(s):  
Zhoujian Zhang ◽  
Michael Liu ◽  
Mark Marley ◽  
Michael Line ◽  
William Best
Keyword(s):  
Physical Properties ◽  
Near Infrared ◽  
Brown Dwarfs ◽  
Spectroscopic Characterization ◽  
Cool Temperature ◽  
Brown Dwarf ◽  
Modeling Framework ◽  
High Quality ◽  
Model Predictions

&lt;p&gt;Spectroscopic characterization of imaged exoplanets and brown dwarfs is essential for understanding their atmospheres, formation, and evolution, but such work is challenged by the unavoidably simplified model atmospheres needed to interpret spectra. While most previous work has focused on single or at most a few objects, comparing a large collection of spectra to models can uncover trends in data-model inconsistencies needed to improve model predictions, thereby leading to robust properties from exoplanet and brown dwarf spectra. Therefore, we are conducting a systematic analysis of a valuable but underutilized resource: the numerous high-quality spectra of (directly imaged and free-floating) exoplanets and brown dwarfs already accumulated by the community.&lt;span class=&quot;Apple-converted-space&quot;&gt;&amp;#160;&lt;/span&gt;&lt;/p&gt; &lt;p&gt;Focusing on the cool-temperature end, we have constructed a Bayesian modeling framework using the new Sonora-Bobcat model atmospheres and have applied it to study near-infrared low-resolution spectra of &gt;50 late-T imaged planets and brown dwarfs (&amp;#8776;600-1200K, &amp;#8776;10-70 M&lt;sub&gt;Jup&lt;/sub&gt;) and infer their physical properties (effective temperature, surface gravity, metallicity, radii, mass). By virtue of having such a large sample of high-quality spectra, our analysis identifies the systematic offsets between observed and model spectra as a function of wavelength and physical properties to pinpoint specific shortcomings in model predictions. We have also found that the spectroscopically inferred metallicities, ages, and masses of our sample all considerably deviate from expectations, suggesting the physical and chemical assumptions made within these models need to be improved to fully interpret data. Our work has established a systematic validation of cloudless model atmospheres to date and we discuss extending such analysis to wider temperature and wavelength (e.g., JWST) ranges, as well as finding new planetary-mass and brown dwarf benchmarks, in order to validate ultracool model atmospheres over larger parameter space.&lt;/p&gt;

scholarly journals Characterization of Optically-Reconfigurable Metasurfaces by a Free Space Microwave Bistatic Technique

2020 ◽  
Vol 10 (12) ◽  
pp. 4353
Author(s):  
Houssemeddine Krraoui ◽  
Charlotte Tripon-Canseliet ◽  
Ivan Maksimovic ◽  
Stefan Varault ◽  
Gregoire Pillet ◽  
...  
Keyword(s):  
Near Infrared ◽  
Optical Power ◽  
Frequency Selective Surface ◽  
Infrared Region ◽  
Photon Absorption ◽  
60 Ghz ◽  
Frequency Range ◽  
Specific Incident ◽  
Absorption Phenomenon

Microwave performance extraction of optically-controlled squared frequency-selective surface (FSS) structures printed on highly resistive (HR) silicon substrate are presented, from a innovative bistatic microwave photonic characterization technique operating in the 40 to 60 GHz frequency range, commonly used for radar cross section (RCS) measurements. According to typical physical photon absorption phenomenon occurring in photoconductive materials, these structures demonstrate experimentally a bandpass filtering frequency response cancellation through reflection coefficient measurements, under specific incident collective illumination in the Near-infrared region (NIR). This behaviour is attributed to their microwave surface impedance modification accordingly to the incident optical power, allowing ultrafast reconfigurability of such devices by optics

scholarly journals Spectroscopic characterization of the protocluster of galaxies around 7C 1756+6520 at z ~ 1.4

2018 ◽  
Vol 618 ◽  
pp. A128 ◽  
Author(s):  
V. Casasola ◽  
L. Magrini ◽  
F. Combes ◽  
E. Sani ◽  
J. Fritz ◽  
...  
Keyword(s):  
Near Infrared ◽  
Radio Galaxy ◽  
High Redshift ◽  
Theoretical Models ◽  
Spectroscopic Characterization ◽  
Emission Lines ◽  
Peculiar Velocities ◽  
Long Time ◽  
High Fraction

Aims. The aim of this paper is the spectroscopic study of 13 galaxies belonging to the field of the protocluster associated with the radio galaxy 7C 1756+6520 at z = 1.4156. In particular, we focus on the characterization of the nuclear activity. Methods. This analysis has been performed on rest-frame optical spectra taken with the Large Binocular Telescope, using the spectrograph LUCI, which is operative in the near-infrared domain. The adopted spectral coverage allowed us to observe emission lines such as Hα, Hβ, [O III]λ 5007 Å, and [N II]λ 6583 Å at the redshift of the central radio galaxy. We observed the central part of the protocluster, which is suitable to include the radio galaxy, several spectroscopically confirmed active galactic nuclei (AGN) belonging to the protocluster, and other objects that might be members of the protocluster. Results. For four previously identified protocluster members, we derived the redshift by detecting emission lines that have never detected before for these galaxies. We identified a new protocluster member and eight new possible protocluster members. The stacked spectrum of the galaxies in which we detected the [O III]λ 5007 Å emission line revealed the second line of the [O III] doublet at 4959 Å and the Hβ line, which confirms that they belong to the protocluster. By collecting all members identified so far in this work and other members from the literature, we defined 31 galaxies, including the central radio galaxy, around the redshift 1.4152 ± 0.056. This corresponds to peculiar velocities ≲5000 km s−1 with respect to the radio galaxy. The position versus velocity phase-space diagram suggests that three AGN of the protocluster and the central radio galaxy might be a virialized population that has been coexisting for a long time in the densest core region of this forming structure. This protocluster is characterized by a high fraction of AGN (~23%). For one of them, AGN1317, we produced two so-called Baldwin, Phillips & Terlevich (BPT) diagrams. The high fraction of AGN and their distribution within the protocluster seem to be consistent with predictions of some theoretical models on AGN growth and feedback. These models are based on galaxy interactions and ram pressure as triggers of AGN activity. Conclusions. The high fraction of AGN belonging to the protocluster suggests that they were likely triggered at the same time, maybe by the ongoing formation of the protocluster. Observations of AGN in this protocluster and in other distant clusters will help clarifying whether the resulting high fraction of AGN is unusual or typical for such structures at high redshift. Our next step will be analyses of previously acquired high-resolution radio data of the central radio galaxy to derive information on the nature of the radio galaxy and connect it with its cosmic evolution.

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