scholarly journals Spectroscopy and Near-Infrared to Visible Upconversion of Er3+ Ions in Aluminosilicate Glasses Manufactured with Controlled Optical Transmission

2021 ◽  
Vol 11 (3) ◽  
pp. 1137
Author(s):  
Daniel Sola ◽  
Adrián Miguel ◽  
Eduardo Arias-Egido ◽  
Jose I. Peña
Keyword(s):  
Energy Transfer ◽  
Spectral Range ◽  
Optical Transmission ◽  
Near Infrared ◽  
Upconversion Luminescence ◽  
Excited State Absorption ◽  
Visible Spectral Range ◽  
Excitation Spectra ◽  
Aluminosilicate Glasses ◽  
Energy Transfer Upconversion

In this work we report on the spectroscopic properties and the near-infrared to visible upconversion of Er3+ ions in aluminosilicate glasses manufactured by directionally solidification with the laser floating zone technique. Glasses were manufactured in a controlled oxidizing atmosphere to provide them with high optical transmission in the visible spectral range. Absorption and emission spectra, and lifetimes were assessed in both the visible and the near infrared spectral range. Green upconversion emissions of the 2H11/2→4I15/2 and 4S3/2→4I15/2 transitions at 525 nm and 550 nm attributed to a two-photon process were observed under excitation at 800 nm. Mechanisms responsible for the upconversion luminescence were discussed in terms of excited state absorption and energy transfer upconversion processes. Excitation spectra of the upconverted emission suggest that energy transfer upconversion processes are responsible for the green upconversion luminescence.

scholarly journals Efficient near-infrared quantum cutting by cooperative energy transfer in Bi3TeBO9:Nd3+ phosphors

2022 ◽  
Author(s):  
T. Zhezhera ◽  
P. Gluchowski ◽  
M. Nowicki ◽  
M. Chrunik ◽  
A. Majchrowski ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Spectral Range ◽  
Near Infrared ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Infrared Emission ◽  
Fluorescence Decay ◽  
Visible Spectral Range ◽  
Visible Radiation ◽  
Quantum Cutting

Abstract An efficient near-infrared quantum cutting process by cooperative down-conversion of active Bi3+ and Nd3+ ions was demonstrated in Bi3TeBO9:Nd3+ phosphors. In particular, the near-infrared emission of Nd3+ ions enhanced by Bi3+ ions of a series of novel Bi3TeBO9:Nd3+ microcrystalline powders doped with Nd3+ ions in various concentrations was investigated. In order to investigate the luminescent properties of BTBO:Nd3+ powders, the excitation and emission spectra and the fluorescence decay time were measured and analyzed. In particular, the emission of Bi3TeBO9:Nd3+ at 890 and 1064 nm was excited at 327 nm (via energy transfer from Bi3+ ions) and at 586.4 nm (directly by Nd3+ ions). The highest intensity emission bands in near-infrared were detected in the spectra of Bi3TeBO9:Nd3+ doped with 5.0 and 0.5 at.% of Nd3+ ions upon excitation in ultraviolet and visible spectral range, respectively. The fluorescence decay lifetime monitored at 1064 nm for Bi3TeBO9:Nd3+ powders shows the single- or double-exponential character depending on the concentrations of Nd3+ ions. The possible mechanisms of energy relaxation after excitation Bi3TeBO9:Nd3+ powders in ultraviolet or visible spectral range were discussed. The investigated Bi3TeBO9:Nd3+ phosphors efficiently concentrate the ultraviolet/visible radiation in the near-infrared spectral range and can be potentially used as effective spectral converters. Graphical abstract

scholarly journals Multiband emission from single β-NaYF4(Yb,Er) nanoparticles at high excitation power densities and comparison to ensemble studies

Nano Research ◽  
2021 ◽  
Author(s):  
Florian Frenzel ◽  
Christian Würth ◽  
Oleksii Dukhno ◽  
Frédéric Przybilla ◽  
Lisa M. Wiesholler ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Single Particle ◽  
Near Infrared ◽  
Upconversion Luminescence ◽  
Excited State Absorption ◽  
High Energy ◽  
Excitation Power ◽  
Relaxation Processes ◽  
Excitation Power Density ◽  
Radiative Relaxation

AbstractEnsemble and single particle studies of the excitation power density (P)-dependent upconversion luminescence (UCL) of core and core-shell β-NaYF4:Yb,Er upconversion nanoparticles (UCNPs) doped with 20% Yb3+ and 1% or 3% Er3+ performed over a P regime of 6 orders of magnitude reveal an increasing contribution of the emission from high energy Er3+ levels at P > 1 kW/cm2. This changes the overall emission color from initially green over yellow to white. While initially the green and with increasing P the red emission dominate in ensemble measurements at P < 1 kW/cm2, the increasing population of higher Er3+ energy levels by multiphotonic processes at higher P in single particle studies results in a multitude of emission bands in the ultraviolet/visible/near infrared (UV/vis/NIR) accompanied by a decreased contribution of the red luminescence. Based upon a thorough analysis of the P-dependence of UCL, the emission bands activated at high P were grouped and assigned to 2–3, 3–4, and 4 photonic processes involving energy transfer (ET), excited-state absorption (ESA), cross-relaxation (CR), back energy transfer (BET), and non-radiative relaxation processes (nRP). This underlines the P-tunability of UCNP brightness and color and highlights the potential of P-dependent measurements for mechanistic studies required to manifest the population pathways of the different Er3+ levels.

scholarly journals Upconversion Luminescence of Silica–Calcia Nanoparticles Co-doped with Tm3+ and Yb3+ Ions

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 937
Author(s):  
Katarzyna Halubek-Gluchowska ◽  
Damian Szymański ◽  
Thi Ngoc Lam Tran ◽  
Maurizio Ferrari ◽  
Anna Lukowiak
Keyword(s):  
Energy Transfer ◽  
Near Infrared ◽  
Upconversion Luminescence ◽  
Sol Gel ◽  
Emission Spectra ◽  
Transmission Electron ◽  
Characteristic Emission ◽  
Diffraction Patterns ◽  
Size Of Particles ◽  
Average Size

Looking for upconverting biocompatible nanoparticles, we have prepared by the sol–gel method, silica–calcia glass nanopowders doped with different concentration of Tm3+ and Yb3+ ions (Tm3+ from 0.15 mol% up to 0.5 mol% and Yb3+ from 1 mol% up to 4 mol%) and characterized their structure, morphology, and optical properties. X-ray diffraction patterns indicated an amorphous phase of the silica-based glass with partial crystallization of samples with a higher content of lanthanides ions. Transmission electron microscopy images showed that the average size of particles decreased with increasing lanthanides content. The upconversion (UC) emission spectra and fluorescence lifetimes were registered under near infrared excitation (980 nm) at room temperature to study the energy transfer between Yb3+ and Tm3+ at various active ions concentrations. Characteristic emission bands of Tm3+ ions in the range of 350 nm to 850 nm were observed. To understand the mechanism of Yb3+–Tm3+ UC energy transfer in the SiO2–CaO powders, the kinetics of luminescence decays were studied.

scholarly journals Enhanced optical transmission through a star-shaped bull’s eye at dual resonant-bands in UV and the visible spectral range

2015 ◽  
Vol 23 (14) ◽  
pp. 18589 ◽  
Author(s):  
Tavakol Nazari ◽  
Reza Khazaeinezhad ◽  
Woohyun Jung ◽  
Boram Joo ◽  
Byung-Joo Kong ◽  
...  
Keyword(s):  
Spectral Range ◽  
Optical Transmission ◽  
Visible Spectral Range ◽  
Enhanced Optical Transmission ◽  
Bull's Eye

Near-infrared broadband cavity-enhanced sensor system for methane detection using a wavelet-denoising assisted Fourier-transform spectrometer

The Analyst ◽  
2018 ◽  
Vol 143 (19) ◽  
pp. 4699-4706 ◽  
Author(s):  
Kaiyuan Zheng ◽  
Chuantao Zheng ◽  
Zidi Liu ◽  
Qixin He ◽  
Qiaoling Du ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Spectral Range ◽  
Near Infrared ◽  
Wavelet Denoising ◽  
Visible Spectral Range ◽  
Sensor System ◽  
Trace Gas ◽  
Fourier Transform Spectrometer ◽  
Methane Detection

The majority of broadband cavity-enhanced systems are used to detect trace gas species in the visible spectral range.

scholarly journals Crystallization and visible–near-infrared luminescence of Bi-doped gehlenite glass

2018 ◽  
Vol 5 (12) ◽  
pp. 181667 ◽  
Author(s):  
M. Majerová ◽  
R. Klement ◽  
A. Prnová ◽  
J. Kraxner ◽  
E. Bruneel ◽  
...  
Keyword(s):  
Spectral Range ◽  
Near Infrared ◽  
Broad Band ◽  
Visible Spectral Range ◽  
Peak Temperature ◽  
Minor Amount ◽  
Glass Microspheres ◽  
Scanning Calorimetry ◽  
Crystallization Peak ◽  
High Temperature Xrd

Gehlenite glass microspheres, doped with a different concentration of Bi 3+ ions (0.5, 1, 3 mol%), were prepared by a combination of solid-state reaction followed by flame synthesis. The prepared glass microspheres were characterized from the point of view of surface morphology, phase composition, thermal and photoluminescence (PL) properties by optical and scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and PL spectroscopy. The closer inspection of glass microsphere surface by SEM confirmed a smooth surface. This was further verified by XRD. The basic thermal characteristics of prepared glasses, i.e. T g (glass transition temperature), T x (onset of crystallization peak temperature), T f (temperature of the inflection point of the crystallization peak) and T p (maximum of crystallization peak temperature), were estimated from the DSC records. High-temperature XRD experiments in the temperature interval range 600–1100°C were also performed. The PL emission properties of prepared glasses and their polycrystalline analogues (glass crystallized at 1000°C for 10 h) were studied in the visible and near-infrared (NIR) spectral range. When excited at 300 nm, the glasses, as well as their polycrystalline analogues, exhibit broad emission in the visible spectral range from 350 to 650 nm centred at about 410–450 nm, corresponding to Bi 3+ luminescence centres. The emission intensity of polycrystalline samples was found to be at least 30 times higher than the emission of their glass analogues. In addition, a weak emission band was observed around 775 nm under 300 nm excitation. This band was attributed to the presence of a minor amount of Bi 2+ species in prepared samples. In the NIR spectral range, the broad band emission was observed in the spectral range of 1200–1600 nm with the maxima at 1350 nm. The chemistry of Bi and its oxidation state equilibrium in glasses and polycrystalline matrices is discussed in detail.

Optical Spectroscopy as a Tool for Observation of Porous SiC Graphitization

2005 ◽  
Vol 483-485 ◽  
pp. 261-264
Author(s):  
V.B. Shuman ◽  
N.S. Savkina
Keyword(s):  
Thermal Treatment ◽  
Absorption Coefficient ◽  
Porous Layer ◽  
Spectral Range ◽  
Optical Transmission ◽  
Near Infrared ◽  
Wet Oxidation ◽  
Infrared Spectral Range ◽  
Infrared Spectral ◽  
Porous Sic

We have studied effects of thermal treatment in vacuum and wet oxidation on the optical transmission of SiC samples with porous layer on the Si face in the visible and near infrared spectral range. An analysis of changes in the absorption coefficient shows that the process of graphitization in vacuum begins at a temperature below 700°C and can be observed at wet oxidation at 1000°C.

scholarly journals Natural slab photonic crystals in centric diatoms

2019 ◽  
Author(s):  
Johannes W. Goessling ◽  
William P. Wardley ◽  
Martin Lopez Garcia
Keyword(s):  
Photonic Crystal ◽  
Photonic Crystals ◽  
Spectral Range ◽  
Near Infrared ◽  
Light Regulation ◽  
Visible Spectral Range ◽  
Mating Strategies ◽  
Unit Cell ◽  
Critical Parameters ◽  
Centric Diatom

AbstractNatural photonic crystals can serve in mating strategies or as aposematism for animals, but they also exist in some photosynthetic organisms, with potential implications for their light regulation. Some of the most abundant microalgae, named diatoms, evolved a silicate exoskeleton, the frustule, perforated with ordered pores resembling photonic crystals. Here we present the first combined experimental and theoretical characterization of the photonic properties of the diatom girdle, i.e. one of two structures assembling the frustule. We show that the girdle of the centric diatom Coscinodiscus granii is a well-defined slab photonic crystal, causing, under more natural conditions when immersed in water, a pseudogap for modes in the near infrared. The pseudogap disperses towards the visible spectral range when light incides at larger angles. The girdle crystal structure facilitates in-plane propagation for modes in the green spectral range. We demonstrate that the period of the unit cell is one of the most critical factors for causing these properties. The period is shown to be similar within individuals of a long-term cultivated inbred line and between 4 different C. granii cell culture strains. In contrast, the pore diameter had negligible effects upon the photonic properties. We hence propose that critical parameters defining the photonic response of the girdle are highly preserved. Other centric diatom species, i.e. Thalasiosira pseudonana, C. radiatus and C. wailesii, present similar unit cell morphologies with various periods in their girdles. We speculate that evolution has preserved the photonic crystal character of the centric girdle, indicating an important biological functionality for this clade of diatoms.

The Optical Spectra of a-Si:H and a-SiC:H Thin Films Measured by the Absolute Photothermal Deflection Spectroscopy (PDS)

2014 ◽  
Vol 213 ◽  
pp. 19-28 ◽  
Author(s):  
Zdenek Remes ◽  
Ravi Vasudevan ◽  
Karol Jarolimek ◽  
Arno H.M. Smets ◽  
Miro Zeman
Keyword(s):  
Thin Films ◽  
Spectral Range ◽  
Near Infrared ◽  
Energy Gap ◽  
Chemical Vapor ◽  
Visible Spectral Range ◽  
Localized States ◽  
Rf Plasma ◽  
Detection Range ◽  
The Absolute

The new absolute PDS setup allows to measure simultaneously the absolute values of the optical transmittance T, reflectance R and absorptance A spectra in the spectral range 280 2000 nm with the typical spectral resolution 10 nm in ultraviolet and visible spectral range and 20 nm in the near infrared region. The PDS setup provides the dynamic detection range in the optical absorptance up to 4 orders of magnitude using non-toxic liquid perfluorohexane Fluorinert FC72. Here we demonstrate the usability of this setup on a series of intrinsic as well as doped a-Si:H and a-SiC:H thin films deposited on glass substrates by radio frequency (RF) plasma enhanced chemical vapor deposition (CVD) from hydrogen, silane and methane under various conditions. The increase of the Tauc gap with increasing carbon concentration in intrinsic a-SiC:H was observed. The defect-induced localized states in the energy gap were observed in doped a-Si:H as well as undoped a-SiC:H below the Urbach absorption edge.

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