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1.
Ho3+/Yb3+/Tm3+ tridoped LiNbO3 single crystal exhibiting intense upconversion white light under 980?nm excitation has been successfully fabricated by the Czochralski method. The tridoped LiNbO3 single crystal offers power dependent color tuning properties by simply changing excitation power. Efficient three-photon blue upconversion emission and two-photon green and red upconversion emissions have been observed. In addition, the red emission of Ho3+ originates dominantly from the nonradiative decay of green emission. The LiNbO3 with upconversion white light will be a potential laser candidate material. 相似文献
2.
The Er3+ -Yb3+ codoped in Li2O content tungsten -tellurite (TWL) transparent glasses are synthesized and measured the absorption, Raman and upconversion
luminescence (UPL) spectra. At room temperature intense green emission peak at 560 nm ( 4S3/2→4I15/2) and red emission peak at 670 nm ( 4F9/2→4I15/2) of Er3+ observed even at minimum 86 mW pumping power of infrared 980 nm excitation. For structure of the TWL glass, Raman spectrum
result revealed that an important role of WO3 in the formation of glass network linkage with Li2O. Under this influence estimated lifetime of the 4I11/2 of Er3+ was 1.89 μs and due to lower phonon energy of the glass produce strong upconversion signal. The effect of Er2O3 concentration on emission intensity result indicated that green emission intensity initially increase in compare to red emission.
Under the 980 nm pump power variation measured the relatively increases the red emission to the green emission intensity and
analyze the possible upconversion mechanism and process. 相似文献
3.
The Y2O3:R(R = Yb3+, Er3+, Tm3+) nanophosphors were synthesized by a solvothermal method and the temperature dependence of the white upconversion emission was studied using a 975 nm LD. The upconversion emission spectra in 1 mol% Er3+/5 mol% Yb3+/xTm3+ tri-doped Y2O3 nanophosphors were sintered at 1000 °C with x from 0 to 0.5 mol%. The blue emission intensity increases increasing Tm3+ concentration from 0 to 0.5 mol%, because the Tm3+ state can be easily reached due to the 2F7/2 → 2F5/2 transition of Yb3+ near 10,000 cm−1. The Y2O3: Er3+/Yb3+/Tm3+ nanophosphors exhibit upconversion emission from white to green with increasing sintering temperature. The calculated CIE coordinates are located in the white region at a pump power of 700 mW at 1000 °C, and the color coordinates were very similar to the standard white light emission. Their upconversion process was described through energy level diagrams and results of upconversion emission spectra and pump power dependence. 相似文献
4.
The Ca12Al14O33: Yb3+/Yb2+ single phase nano-phosphor has been synthesized through combustion route and its luminescence and lifetime studies have been
carried out up to 20 K using 976 and 266 nm excitations. The samples heated in open atmosphere have shown the presence of
Yb in Yb3+ and Yb2+ states. The 976 nm excitation results a cooperative upconversion emission at 486 nm due to the Yb3+ state and a broad band in the blue region and has been assigned to arise from the defect centers. The 266 nm excitation on
the other hand results a broad emission band even from as-synthesized phosphor without doping of Yb, the width of which increases
in presence of Yb due to the emission from Yb2+ ions formed in heated samples. The white emission covers almost whole visible region with bandwidth 190 nm. The ions in Yb2+ state has been found to increase with the increase in heating temperature up to 1,273 K. A back conversion of Yb2+ to Yb3+ has been observed for higher temperatures. Effect of boric and phosphoric acids as flux on the emission properties of Yb3+ and Yb2+ states have been examined and discussed. Quantum yield of emission has also been determined for different samples. 相似文献
5.
R. Piramidowicz R. Mahiou P. Boutinaud M. Malinowski 《Applied physics. B, Lasers and optics》2011,104(4):873-881
We report the orange-to-blue and infrared-(IR)-to-blue wavelengths upconversion luminescence in Pr3+:BaY2F8 crystals. Mechanism of the orange light upconversion into blue 3P0 state emission was confirmed to be energy transfer between two Pr3+ ions in the 1D2 state. IR-to-blue upconversion has only been observed under two different color IR pumping. The first resonant step was the
3H4→1G4 ground state absorption transition, and the second resonant transition was the excited state absorption from the 1G4 to 1I6 and 3PJ levels. A comparison of the efficiency of the IR-to-blue upconversion in several praseodymium activated host is presented
and discussed. A model of the IR pumped upconversion praseodymium blue laser is presented and the population inversion conditions
are calculated. 相似文献
6.
J. X. Zhang L. Han Y. Wu N. Zong P. Z. Fu B. S. Wang G. C. Zhang Z. Y. Xu Y. C. Wu 《Applied physics. B, Lasers and optics》2011,103(4):853-856
The self-sum-frequency process was firstly demonstrated in Nd3+-doped La2CaB10O19 (LCB) crystal. In addition, simultaneous participation of the fundamental laser in multi-self-frequency conversion including
the self-frequency doubling was reported. Emissions at five different wavelengths (525, 529, 533.6, 1050 and 1069 nm) were
simultaneously obtained. The output power of the three green visible lasers (525, 529 and 533.6 nm) generated by multi-self-frequency-conversion
of the fundamental laser is up to 26.64 mW, and the light-light conversion efficiency is up to 4.85%. The lasers at 525 and
529 nm are very close to the green primary color G (526.3 nm) defined by the 1964CIERGB system, which has potential applications
in laser-based high brightness display. The large frequency differences of 4–6 THz between 525 and 529 nm, 529 and 533.6 nm,
as well as 1050 and 1069 nm, are also potential useful in generating THz waves by difference frequency generation (DFG) technique
in a nonlinear optical (NLO) crystal. 相似文献
7.
A.E. Troshin V.E. Kisel A.S. Yasukevich N.V. Kuleshov A.A. Pavlyuk E.B. Dunina A.A. Kornienko 《Applied physics. B, Lasers and optics》2007,86(2):287-292
The polarized absorption spectra of Tm3+-doped potassium yttrium tungstate (Tm:KY(WO4)2) crystal at room temperature were measured. The emission spectrum and lifetime of the 3
F
4 excited state were determined. Using standard and modified Judd–Ofelt theories, the intensity parameters and the radiative
lifetimes were calculated and good agreement with the experimental results was obtained for both theories. Continuous-wave
laser operation in Tm:KYW crystal under laser diode pumping at 802 nm and 1750 nm was demonstrated with slope efficiency of
53% and 28% and output power of about 555 mW and 86 mW, respectively.
PACS 42.55.Xi; 42.60.Pk; 42.70.Hj 相似文献
8.
Sr6BP5O20:Eu2+ phosphor was prepared by the solid-state reaction method under a weak reductive atmosphere and the photoluminescence properties
were studied systematically. The bluish-green emission band of Sr6BP5O20:Eu2+ phosphor is peaking at 475 nm, and the excitation bands are broad with peaks at about 290 and 365 nm with a shoulder around
390 nm, respectively. By combining with Ga(In)N-based near-ultraviolet LEDs, a bluish-green LED was fabricated based on the
Sr6BP5O20:Eu2+ phosphor, and a novel intense white LED was fabricated based on the bluish-green phosphor Sr6BP5O20:Eu2+ and the red phosphor (Sr,Ca)5(PO4)3Cl:Eu2+,Mn2+. When this two-phosphor white LED is operated under 20-mA forward-bias current at room temperature, the Commission Internationale
de l’Eclairage(CIE) chromaticity coordinates (x,y), the correlated color temperature Tc, and the color rendering index Ra
are calculated to be (0.3281,0.3071), 5687 K, and 87.3, respectively. The dependence of the bluish-green and two-phosphor
white LEDs on different forward-bias currents from 5 mA to 50 mA shows a similar behavior. As the current increases, the relative
intensity simultaneously increases. The CIE chromaticity coordinates (x,y) of the two-phosphor white LED tend to decrease.
Consequently, the correlated color temperature Tc increases from 3800 K to 9400 K and the color rendering index Ra of the
two-phosphor white LED increases from 83.4 to 91.8 simultaneously.
PACS 07.60.-j; 42.70.-a; 71.55.Eq 相似文献
9.
A diode pumped Pr3+:LiYF4 laser at 639.5 nm has been demonstrated. With an incident pump power of 920 mW, the maximum red output power was 272 mW.
Moreover, intracavity second-harmonic generation (SHG) has also been achieved with a maximum ultraviolet power of 23 mW by
using a β-BaB2O4 (BBO) nonlinear crystal. To the best of our knowledge, this is the first report on continuous-wave ultraviolet generation
by intracavity frequency doubling Pr3+:LiYF4 laser. 相似文献
10.
We have demonstrated the continuous wave laser operation of Yb3+:YVO4. For Ti:Al2O3 laser pumping at 985 nm, a maximum slope efficiency of 41.1% and a threshold pump power of 76 mW were obtained. The maximum output power was 433 mW at a laser wavelength of 1037 nm.Using a cw diode laser around 974 nm as a pump source, a slope efficiency of 10.9% and a maximum output power of 152 mW were achieved at a laser wavelength of 1039 nm. The laser threshold pump power was 608 mW with respect to the absorbed pump power. The effective emission cross-sections for the 2F5/22F7/2 transition were determined using the Füchtbauer–Ladenburg equation. The maxima of the effective absorption and emission cross-sections were found at 984.5 nm (6.74×10-20 cm2) in -po larization and 985.5 nm (4.28×10-20 cm2) also in -p olarization. The upper laser level lifetime was measured with suppression of radiation trapping and is around 318 s. PACS 42.55.Rz; 42.55.Xi; 42.70.Hj 相似文献
11.
It is reported that efficient continuous-wave (CW) blue laser generation at 465 nm in a BiB3O6 (BiBO) crystal at type-I phase matching direction performed with a diode-pumped Nd3+:YAlO3 (Nd:YAP) laser. With incident pump power of 18.4 W, output power of 823 mW at 465 nm has been obtained using a 10 mm-long
BiBO crystal. At the output power level of 823 mW, the output stability is better than 2.3%. 相似文献
12.
W. Liang X. H. Zhang J. Xia G. Y. Jin L. J. Xu G. C. Sun Z. M. Zhao 《Laser Physics》2011,21(5):861-863
A high-power diode -pumped Nd3+:YAl3(BO3)4 (Nd:YAB) laser emitting at 1338 nm is described. At the incident pump power of 9.8 W, as high as 734 mW of continuous-wave
(CW) output power at 1338 nm is achieved. The slope efficiency with respect to the incident pump power was 9.0%. To the best
of our knowledge, this is the first demonstration of such a laser system. The output power stability over 60 min is better
than 2.6%. The laser beam quality M
2 factor is 1.21. 相似文献
13.
The Dy3+ and Eu3+ activated K3Al2 (PO4)3 phosphors were prepared by a combustion synthesis. From a powder X-ray diffraction (XRD) analysis the formation of K3Al2 (PO4)3 was confirmed. In the photoluminescence emission spectra, the K3Al2(PO4)3:Dy3+ phosphor emits two distinctive colors: blue and yellow whereas K3Al2(PO4)3:Eu3+ emits red color. Thus the combination of colors gives BYR (blue–yellow–red) emissions can produce white light. These phosphors
exhibit a strong absorption between 340 and 400 nm which suggest that present phosphor is a promising candidate for producing
white light-emitting diodes (LED). 相似文献
14.
The mechanism of the upconversion processes in Y6O5F8: 2%Er3+/X%Yb3+ (X = 3, 10, 20) microtubes has been explored. The luminescent properties of the as prepared sample is investigated by utilizing up- /downconversion, decay and time resolve spectra. The results indicate that the red and green emission are clearly competitive depending on the Yb3+ concentration. High Yb3+ concentration induces the enhancement of the energy-back-transfer (EBT), process, which leads to the quenching of green emission and enhances the red emission. So it is possible to utilize the temporal evolutions of emission bands to deeply understand the color change UC mechanisms. 相似文献
15.
A series of tungsten-tellurite glasses activated with different concentrations (0–1.5 mol %) of Er3+ has been synthesized. The structural properties of the best luminescent sample and the optical properties of its Er3+ ions, are studied both immediate after its preparation as well as after its ageing. On ageing the glass suffers structural
reorganization and generates Er2WO6—nanocrystals in the matrix, which greatly enhances the normal and upconversion green luminescence efficiency of Er3+. The nanocrystal aided enhancement of normal and upconversion luminescence of Er3+ of the glass has been attributed to the crystal field effects of the new environment of Er3+ in the nanocrystals. A phenomenon of preferential enhancement of red upconversion luminescence at the cost of green upconversion
luminescence of Er3+ at its higher concentrations in the glass has been observed and the related photo-physics is proposed. The material shows
the prospect of being used as NIR solar concentrator. 相似文献
16.
This paper reports on the spectroscopic properties and energy transfer analysis of Tm3+-doped BaF2-Ga2O3-GeO2-La2O3 glasses with different Tm2O3 doping concentrations (0.2, 0.5, 2.0, 2.5, 3.0, 3.5, 3.5, 4.0 wt%). Mid-IR fluorescence intensities in the range of 1,300 nm−2,200 nm
have been measured when excited under an 808 nm LD for all the samples with the same pump power. Energy level structure and
Judd-Ofelt parameters have been calculated based on the absorption spectra of Tm3+, cross-relaxation rates and multi-phonon relaxation rates have been estimated with different Tm2O3 doping concentrations. The maximum fluorescence intensity at around 1.8 μm has been obtained in Tm2O3-3 wt% sample and the maximum value of calculated stimulated emission cross-section of Tm3+ in this sample is about 0.48 × 10−20 cm2 at 1,793 nm, and there is not any crystallization peak in the DSC curve of this sample, which indicate the potential utility
of Tm3+-doped BaF2-Ga2O3-GeO2- La2O3 glass for 2.0-μm optical fiber laser. 相似文献
17.
We report spectroscopic and laser properties for propagation directions outside the principal axes of Yb3+-doped low symmetry laser crystals with a special devotion to the wavelength dependence anisotropy. We illustrate our report
with experimental data in the 900–1075 nm range of wavelengths from the Yb3+:La2CaB10O19 monoclinic crystal excited under laser diode pumping at 975 nm. This study, which makes easier the realization of Yb3+ lasers with an efficient free-running operation at the wavelength having the highest emission intensity or at a specified
wavelength, or emitting two frequencies with a specified frequency difference, is of promising interest for applications. 相似文献
18.
Hua Lai Amurisana Bao Yuming Yang Yanchun Tao Hua Yang 《Journal of nanoparticle research》2008,10(8):1355-1360
Eu3+-doped (La, Ln) PO4 (Ln = Gd and Y) phosphors were prepared by a facile co-precipitation method. Their structures and luminescent properties
under UV excitation were investigated. Structural characterization of the nanostructured luminescence material was carried
out with X-ray powder diffraction analysis. Scanning electron microscopy was carried out to understand the surface morphological
features and grain sizes with 50–100 nm. It is found that (La, Gd) PO4:Eu3+ phosphors have the same crystal structure as LaPO4:Eu3+, which is monoclinic with a little different lattice parameters. In the case of (La, Y) PO4:Eu3+ phosphors, however, the gradual change from monoclinic to tetragonal structure of host lattice was observed, as the amount
of Y ion increased. From the photoluminescence spectra for (La, Ln) PO4:Eu3+ (Ln = Gd and Y), the emission transition 5D0 → 7F1 has been found to be more prominent over the normal red emission transition 5D0 → 7F2. Furthermore, the size influence on the products was discussed. It was observed that the spectral features possess sharp
and bright emission for potential applications on the monitors of the television and some other related electronic systems,
in observing the images in orange–red color. 相似文献
19.
N.A. Tolstik A.E. Troshin S.V. Kurilchik V.E. Kisel N.V. Kuleshov V.N. Matrosov T.A. Matrosova M.I. Kupchenko 《Applied physics. B, Lasers and optics》2007,86(2):275-278
We report on the spectroscopy and, for the first time to our knowledge, continuous-wave and Q-switched diode-pumped laser
operation of Er,Yb:YVO4 crystal. Absorption and emission spectra of the crystal were determined. Lifetimes of Er3+
4
I
13/2 and 4
I
11/2 levels that define laser performance of the crystal were measured and parameters of energy transfer between Yb3+ and Er3+ ions were estimated. cw output power of 115 mW with slope efficiency of 5.4% was achieved at 1604 nm. In the Q-switched mode
an average output power of 81 mW with slope efficiency of 3.5% and pulse duration of 150 ns was obtained. In quasi-cw regime
maximal peak power of 610 mW with slope efficiency of 6.7% was demonstrated.
PACS 42.55.Xi; 42.60.Gd; 42.70.Hj 相似文献
20.
It is reported that efficient continuous-wave (CW) red laser generation at 670 nm in a LBO crystal at type-I phase matching
direction performed with a diode-pumped Nd3+:YAlO3 (Nd:YAP) laser. With incident pump power of 15.6 W, output power of 273 mW at 670 nm has been obtained using a 10 mm-long
LBO crystal. At the output power level of 273 mW, the output stability is better than 3.7%. 相似文献