scholarly journals Structure of Centers of Matrix Emission of the Undoped and RE-Doped Scheelite-Type Lead Tungstate Crystals

2019 ◽  
Vol 64 (9) ◽  
pp. 837
Author(s):  
O. Chukova ◽  
S. Nedilko
Keyword(s):  
Rare Earth ◽  
Emission Spectra ◽  
Luminescence Spectra ◽  
Lead Tungstate ◽  
Luminescence Centers ◽  
Individual Bands

The paper reports the investigation of a structure of luminescence spectra of PbWO4 (PWO) crystals. The doping of the samples with rare earth (RE) impurities is used in order to obtain more information about the composition of spectra of the PWO matrix emission and the structure of its luminescence centers. The decomposition of the emission spectra onto individual bands has shown that 5 bands contribute to the total spectra of all the undoped and RE-doped samples at 10 K. The maxima of the obtained bands are 1.95, 2.2, 2.45, 2.7, and 3.0 eV. Effects of the RE-doping and the annealing on relative intensities of these bands are considered. The nature of luminescence and the structure of the centers involved in the excitation and emission processes responsible for each of the separated bands are discussed.

Luminescence of Er3+/Nd3+ Co-Doped Lithium Niobate Tellurite Glass

2016 ◽  
Vol 846 ◽  
pp. 131-136
Author(s):  
Nurhafizah Hasim ◽  
Md Supar Rohani ◽  
Md Rahim Sahar ◽  
Sib Krishna Ghoshal
Keyword(s):  
Rare Earth ◽  
Lithium Niobate ◽  
Excited States ◽  
Ground State ◽  
Emission Spectra ◽  
Green Emission ◽  
Volume Density ◽  
Rare Earth Ions ◽  
Luminescence Spectra ◽  
Co Doped

Achieving tuneable photoluminescence via controlled co-doping of rare earth ions in lithium niobate based glasses are challenging. A series of Er3+/ Nd3+ co-doped tellurite glasses of composition (70-x-y) TeO2 – 15 Li2CO3 – 15 Nb2O5 – (x) Er2O3 – (y) Nd2O3 with x = 0; 1.0 mol % and 0 ≤ y ≤ 1.0 mol % are prepared using melt quenching technique. The influence of co-dopants on the emission properties is analyzed and discussed using partial energy level diagram of rare earth ions. The dopants concentration dependent physical properties such as refractive index, molar volume, density, polarizability and molar refractions are determined. The down-converted luminescence spectra for 2G9/2 à4I9/2 transition reveal a strong green emission band centred at 497 nm is attributed to the energy transfer from erbium to neodymium ion. The emission spectra exhibit five prominent peaks centred at 497, 539, 553, 616 and 634 nm corresponding to the transitions from 2H11/2, 4S3/2 and 4F9/2 excited states to the ground state of Er3+ ion and the transitions from 2G9/2, 2G7/2, 2H11/2 and 4F9/2 excited states to ground state of Nd3+ ion. The highest intensity is achieved for x = y = 1.0 mol%. The excellent luminescence response suggests that our glasses may be nominated for solid state lasers and other photonic applications.

NIR and Upconversion Luminescence Properties of Nd3+ Doped in Gd2O3-CaO-SiO2-B2O3 Glass System

2014 ◽  
Vol 548-549 ◽  
pp. 124-128 ◽  
Author(s):  
S. Insiripong ◽  
S. Kaewjeang ◽  
U. Maghanemi ◽  
H.J. Kim ◽  
N. Chanthima ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Upconversion Luminescence ◽  
Emission Spectra ◽  
Concentration Quenching ◽  
Luminescence Spectra ◽  
Optical Absorption Spectra ◽  
Glass Matrices ◽  
Nir Luminescence

In this work, properties of Nd3+ in Gd2O3-CaO-SiO2-B2O3 glass systems with composition 25Gd2O3-10CaO-10SiO2-(55-x)B2O3-xNd2O3 where x = 0.0, 0.5, 1.0, 1.5, 2.0 and 2.5 mol% were investigated. The optical absorption spectra show peaks at 4F3/2 (877 nm) , 4F5/2+2H9/2 (802 nm), 4F7/2+4S3/2 (743 nm), 4F9/2 (682 nm), 2H11/2 (627 nm), 2G7/2 +4G5/2 (582 nm), 4G7/2 +2K13/2 (527 nm), 4G11/2 (481 nm), 2P1/2 (427 nm) and 2L15/2 + 4D1/2 + 1I11/2+ 4D5/2+ 4D3/2 (355 nm) reflecting the Nd3+ ions in glass matrices. The densities were increased with increasing of Nd2O3 concentration. This indicates the increase of the molecular weight by the replacement of B2O3 with a heavier Nd2O3 oxide in the glass. The upconversion luminescence spectra show bands at 393 nm for all Nd2O3 concentration and the strongest intensity from 2.5 % mol of Nd2O3 was obtained. For NIR luminescence, the intensity of Nd3+ emission spectra increases with increasing concentrations of Nd3+ up to 1.5 mol% and beyond 1.5 mol% the concentration quenching is observed.

RARE-EARTH DOPED POTASSIUM LEAD BROMIDE MID-IR LASER SOURCES FOR STANDOFF DETECTION

2008 ◽  
Vol 18 (03) ◽  
pp. 735-745 ◽  
Author(s):  
KRISHNA C. MANDAL ◽  
SUNG H. KANG ◽  
MICHAEL CHOI ◽  
R. DAVID RAUH
Keyword(s):  
Rare Earth ◽  
Emission Spectra ◽  
Optical Quality ◽  
Scanning Calorimetry ◽  
Laser Applications ◽  
Excellent Thermal Stability ◽  
Standoff Detection ◽  
Lead Bromide ◽  
Vertical Bridgman ◽  
Laser Crystals

The single crystal growth of KPb 2 Br 5 by vertical Bridgman technique using in-house processed zone refined PbBr 2 and KBr with rare-earth terbium doping has been studied. The grown moisture resistant crystals (1.5 cm diameter and 10 cm length) have shown high promise for low phonon energy room temperature solid-state laser applications in the longer side of mid-IR (4-15 µm) due to their high storage lifetimes, wide tunability, and excellent optical quality. The processed crystals are highly transparent ( T = ≥80%) in the 0.4-25 µm spectral region. Repeated melting-freezing cycles during differential scanning calorimetry (DSC) experiments did not reveal any appreciable variation in the melting point or phase transitions, which is indicative of their excellent thermal stability. The emission spectra pumped with a 2 µm source show broadband emissions with peak wavelength of 3 µ m (7 F 4→ 7 F6), 5µ m (7 F 5→ 7 F 6) and 7.9µ m (7 F 4→ 7 F 5). The KPb 2 Br 5: Tb laser crystals will be highly useful for standoff detection of incoming chemical and biological threats using unique infrared absorption signatures.

Band-Gap Energy Dependence of Emission Spectra in Rare Earth-Doped Zn(1-x)CdxS Thin Film Electroluminescent Devices

1992 ◽  
Vol 31 (Part 1, No. 2A) ◽  
pp. 295-300 ◽  
Author(s):  
Noboru Miura ◽  
Takashi Sasaki ◽  
Hironaga Matsumoto ◽  
Ryotaro Nakano
Keyword(s):  
Thin Film ◽  
Rare Earth ◽  
Band Gap ◽  
Energy Dependence ◽  
Emission Spectra ◽  
Band Gap Energy ◽  
Electroluminescent Devices ◽  
Gap Energy ◽  
Rare Earth Doped

ELECTRON STRUCTURE INVESTIGATIONS OF InGaP/GaAs(100) HETEROSTRUCTURES WITH InP QUANTUM DOTS

2007 ◽  
Vol 06 (03n04) ◽  
pp. 215-219
Author(s):  
E. P. DOMASHEVSKAYA ◽  
V. A. TEREKHOV ◽  
V. M. KASHKAROV ◽  
S. YU. TURISHCHEV ◽  
S. L. MOLODTSOV ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Emission Spectra ◽  
Luminescence Spectra ◽  
Partial Density ◽  
Edge Structure ◽  
X Ray ◽  
Metal Organic ◽  
Structure Investigations ◽  
First Time ◽  
Inp Quantum Dots

Ultrasoft X-ray emission spectra (USXES) and X-ray absorption near-edge structure (XANES) spectra with the use of synchrotron radiation in the range of P L2,3-edges were obtained for the first time for nanostructures with InP quantum dots grown on GaAs 〈100〉 substrates by vapor-phase epitaxy from metal–organic compounds. These spectra represent local partial density of states in the valence and conduction bands. The additional XANES peak is detected; its intensity depends on the number of monolayers forming quantum dots. Assumptions are made on the band-to-band origin of luminescence spectra in the studied nanostructures.

Quantum-Confined Optical Interband Transitions in 5-Doped Doping Superlattices

1989 ◽  
Vol 145 ◽  
Author(s):  
E. F. Schubert ◽  
T. D. Harris ◽  
J. E. Cunningham
Keyword(s):  
Emission Spectra ◽  
Doping Profile ◽  
Luminescence Spectra ◽  
Interband Transitions ◽  
Doping Technique ◽  
Quantum Confined ◽  
P Type ◽  
First Time ◽  
Experimental Absorption ◽  
Good Agreement

AbstractOptical absorption and photoluminescence experiments are performed on GaAs doping superlattices, which have a δ-function-like doping profile of alternating n-type and p-type dopant sheets. Absorption and emission spectra reveal for the first time the clear signature of quantum-confined interband transitions. The peaks of the experimental absorption and luminescence spectra are assigned to calculated energies of quantum-confined transitions with very good agreement. It is shown that the employment of the δ-doping technique results in improved optical properties of doping superlattices.

Study on the equivalent luminance of luminous fibers in photopic vision and scotopic vision

2017 ◽  
Vol 88 (10) ◽  
pp. 1157-1163 ◽  
Author(s):  
Yanhong Yan ◽  
Chengxia Liu ◽  
Xiaojun Ding
Keyword(s):  
Experimental Data ◽  
Rare Earth ◽  
Melt Spinning ◽  
Emission Spectra ◽  
Scotopic Vision ◽  
Photopic Vision ◽  
Earth Material ◽  
Long Afterglow ◽  
Polyamide Fiber ◽  
Spinning Process

Colored luminous fibers were prepared by a melt spinning process, adding colored pigments and long afterglow rare earth material into polyamide fiber. The colored luminous fibers had a variety of colors in photopic vision, and emitted colored light in mesopic vision and scotopic vision. Based on the experimental data of the emission spectra and the test luminance of the luminous fibers, the effect of the emissive colors of the luminous fibers on the equivalent luminance at different vision states was analyzed. The results showed that the effect of the emissive colors of white, red, yellow, and green luminous fibers on the equivalent luminance was not obvious in photopic and scotopic vision, but that of blue luminous fiber was obvious in photopic vision but not in scotopic vision.

Samarium Ions Concentration Dependent Optical Enhancement in Phosphate Glass

2015 ◽  
Vol 1107 ◽  
pp. 449-453
Author(s):  
Ramli Arifin ◽  
Lee Pei San ◽  
Md Rahim Sahar ◽  
Sib Krishna Ghoshal ◽  
Khaidzir Hamzah
Keyword(s):  
Rare Earth ◽  
Chemical Composition ◽  
Absorption Spectra ◽  
Phosphate Glass ◽  
Emission Spectra ◽  
Photonic Devices ◽  
Phosphate Glasses ◽  
Significant Enhancement ◽  
Melt Quenching ◽  
Nir Absorption

Glasses activated rare earth (RE) ions are demanding for photonic devices. Optimization of rare earth dopants, chemical composition of glass former and modifier decides spectra features. We synthesize a series of glass having composition (50-x)P2O5 - 30Li2O - 20Na2O - (x)Sm2O3, where x = 0 to 2.0 mol% (optimizing RE concentration) via melt-quenching technique. The effects of Sm2O3 concentration on significant enhancement of absorption and luminescence are scrutinized. The UV-Vis-NIR absorption spectra reveal ten band and the emission spectra exhibit four peaks specific to the dopant. The results suggest that samarium doped phosphate glasses are potential for laser and other applications.

scholarly journals The Temperature Dependence of Fundamental Photophysical Properties of [Eu(MeOH-d4)9]3+ Solvates and [Eu.DOTA(MeOH-d4)]- Complexes

2021 ◽  
Author(s):  
Nicolaj Kofod ◽  
Lea Gundorff Nielsen ◽  
Thomas Just Sørensen
Keyword(s):  
Transition Probabilities ◽  
Photophysical Properties ◽  
Transition Probability ◽  
Energy Levels ◽  
Emission Spectra ◽  
Lanthanide Ions ◽  
Quantum Yields ◽  
Luminescence Spectra ◽  
Absorption Cross ◽  
Apparent Lack

The trivalent lanthanide ions show optical transitions between energy levels within the 4f shell. All these transitions are formally forbidden according to the quantum mechanical selection rules used in molecular photophysics. Nevertheless, highly luminescent complexes can be achieved, and terbium(iii) and europium(iii) ions are particularly efficient emitters. This report started when an apparent lack of data in the literature led us to revisit the fundamental photophysics of europium(iii). The photophysical properties of two complexes – [Eu.DOTA(MeOH-d4)]- and [Eu(MeOH-d4)9]3+ – were investigated in deuterated methanol at five different temperatures. Absorption spectra showed decreased absorption cross sections as the temperature was increased. Luminescence spectra and time-resolved emission decay profiles showed a decrease in intensity and lifetime as a temperature was increased. Having corrected the emission spectra for the actual number of absorbed photons and differences in non-radiative pathways, the relative emission probability was revealed. These were found to increase with increasing temperature. The transition probability for luminescence was shown to increase with temperature, while the transition probability for light absorption decreased. The changes in transition probabilities were correlated to a change in the symmetry of the absorber or emitter, with an average increase in symmetry lowering absorption cross section and access to more asymmetric structures increasing the emission rate constant. Determining luminescence quantum yields and the Einstein coefficient for spontaneous emission allowed us to conclude that lowering symmetry increases both. Further, it was found that collisional self-quenching is an issue for lanthanide luminescence, when high concentrations are used. Finally, detailed analysis revealed results that show the so-called ‘Werts’ method’ for calculating radiative lifetimes and intrinsic quantum yields are based on assumption that does not hold for the two systems investigated here. We conclude that we are lacking a good theoretical description of the intraconfigurational f-f transition, and that there are still aspects of fundamental lanthanide photophysics to be explored.<br>

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