共查询到20条相似文献,搜索用时 0 毫秒
1.
Yan ZhangShengzhi Zhao Dechun LiKejian Yang Guiqiu LiGang Zhang Kang Cheng 《Optical Materials》2011,33(3):303-307
By using both acousto-optic modulator and GaAs saturable absorber, a diode-pumped Q-switched and mode-locked(QML) YVO4/Nd:YVO4/KTP green laser is presented. The experimental results show that the doubly QML YVO4/Nd:YVO4/KTP green laser has good stability and nearly 100% modulation depth. The average output power and the pulse width of the Q-switched envelope have been measured. The mode-locked pulse inside the Q-switched envelope has a repetition rate of 137 MHz and its pulse width is estimated to be about 280 ps. By using a hyperbolic secant square function and considering the Gaussian distribution of the intracavity photon density, the coupled equations for diode-pumped dual-loss-modulated QML green laser is given and the numerical solutions of the equations are in good agreement with the experimental results. 相似文献
2.
A diode-pumped doubly Q-switched and mode-locked (QML) YVO4/NdYVO4 laser is realized with the electro-optic (EO) modulator and Cr4+:YAG saturable absorber, in which the repetition rate of the Q-switched envelope is controlled by the active EO modulation while the mode-locked pulses inside the Q-switched envelope depend on both the actively modulated loss and the passive saturable absorption. The experimental results show that the doubly QML laser can generate more stable and shorter pulses with higher peak power when compared with the singly passively QML laser with Cr4+:YAG. At the pump power of 20 W and the repetition rate 1 kHz, a 21 ns Q-switched pulse envelope with a average mode-locked peak power of 544 kW is obtained, which is the shortest Q-switched pulse envelope to my knowledge. In comparison to the singly passively QML laser with Cr4+:YAG, the doubly QML laser has compressed the Q-switched envelope pulse width 70% and improved the mode-locked pulsed peak power 27 times. By using a hyperbolic secant square function and considering the Gaussian distribution of the intracavity photon density, the coupled equations for diode-pumped dual-loss-modulated QML laser is given and the numerical solutions of the equations are in good agreement with the experimental results. 相似文献
3.
This paper reports the luminescence effects of Tm3+ doped YVO4:Dy nanocrystalline synthesized by a modified Pechini method. The structure and morphology were characterized by using X-ray diffraction (XRD) and transmission electron microscope (TEM). The relationship between the ratio of Tm3+/Dy3+ and the chromaticity is studied, i.e. Tm3+ ion doping effectively tunes the emission color of YVO4:TmxDy1−x phosphors. The best white light emission was observed with YVO4:1%(Tm0.6Dy0.4). These results indicate that thulium doped YVO4:Dy phosphors are promising white-emitting luminescence materials. 相似文献
4.
A well oriented YVO4 single crystal, with 5% Yb3+ and 2% Tm3+ nominal doping, was investigated using the Raman and EPR techniques.The EPR measurements suggest that Yb3+ ions occupy eight-coordinated Y3+ sites forming bisdisphenoids of the D2d symmetry. An inhomogeneous distribution of rare-earth ions leads to a significant distortion of the local point symmetry (C1). It seems that strong dipole–dipole interactions between Yb3+ ions are responsible for the distortion. As a result, two types of ytterbium magnetic centers appear. They correspond to paired magnetic centers and distorted isolated paramagnetic centers that are strongly sensitive to the magnetic field directions and some imperfections of the crystal. Pair centers can be recorded through the rotation around the c-crystal axis, whereas isolated centers can be measured when the crystal is rotated around the a-crystal axis. With the increasing temperature, the ytterbium signal disappeared at about 23 K and a group of narrow lines became visible. These lines, observed in the range of 240–550 mT, correspond to the Gd3+ (S = 7/2) ions, doped to the structure unintentionally from the basic materials. 相似文献
5.
Yu-Jie Ma Fei Lu Jiao-Jian Yin Chang-Dong Ma 《Materials Science and Engineering: B》2013,178(20):1464-1468
Damage formation mechanism of Nd:YVO4 implanted with MeV ions is investigated. MeV Si+ ions were implanted into Nd:YVO4 crystal, and the lattice damage was measured using Rutherford backscattering spectroscopy/channeling (RBS/C) method. The damage creation kinetic indicates a significant contribution from electronic energy loss to the surface damage. A detailed analysis allows us to deduce the different contributions from electronic and nuclear stopping powers to the lattice damage production. An obvious difference in extent of damage from 1 MeV and 3 MeV Si+ implantations also implies that there exists a threshold value of the electronic energy deposition for damage formation. The exact value of threshold is obtained by comparison with the experimental data obtained from 3 MeV O+, F+ and Si+ implantation results, which turns out to be (1.7 ± 0.1) keV/nm. 相似文献
6.
In this work, erbium, and erbium and ytterbium co-doped YVO4 waveguiding thin films were deposited on amorphous SiO2 substrates by pulsed laser deposition (PLD) and ultraviolet-assisted pulsed laser deposition (UVPLD). The influence of the deposition technique on the structure, morphology, and optical properties of the films was investigated. At lower dopant concentrations the films prepared by UVPLD show better crystallinity and optical properties. All the samples show preferred orientation of the (001) zone axes parallel to the substrate surface. The polycrystalline samples show difference in the refractive indexes ?n (?n = nTE − nTM) for the TE and TM polarizations. 相似文献
7.
The tetragonal YVO4 nanocrystals are facilely prepared via a hydrothermal solid-phase synthesis method directly utilizing bulk phase materials of V2O5 and Y2O3 as precursor. Whether additives (acid and EDTA) exist or not, the reaction can be performed in the mild temperature range from 130 to 200 °C. The products are characterized with XRD, FTIR, TEM and PL. The effect of acid and amounts of EDTA on the morphology of the product is investigated. The YVO4 nanoparticles exhibit novel photoluminescence emission bands at 330 and 606 nm under 254 nm excitation. A growth mechanism of yttrium orthovanadate is proposed. 相似文献
8.
YVO4 single crystals doped with Ce3+, Er3+ and Yb3+ ions were grown by the Czochralsski technology. The luminescence properties of Er3+/Yb3+:YVO4 single crystals with different concentration of Ce3+ were studied, and the energy transfer mechanism between Er3+, Yb3+ and Ce3+ was discussed based on their energy level properties. The branching ratios of the 4I11/2 → 4I13/2 transition in different samples were calculated. The results indicate that codopants of Ce3+ greatly enhance the population rate of the 4I13/2 level due to the fast resonant energy transfer between Er3+ and Ce3+, i.e., 4I11/2(Er3+) + 2F7/2(Ce3+) → 4I13/2(Er3+) + 2F5/2(Ce3+). 相似文献
9.
J. W. Shur V. V. Kochurikhin A. E. Borisova M. A. Ivanov D. H. Yoon 《Optical Materials》2004,26(4):347
Nd-doped YVO4 crystal is an excellent material for making the diode-pumped solid lasers. In this study, Nd-doped YVO4 multi-crystal with high quality was grown simultaneously by developed edge-defined film-fed growth (EFG) method. All crystals appeared homogenous Nd distribution and were found the stable step-faceting phenomena. The up-conversion properties on the Nd:YVO4 multiple-crystal have been measured by the observations of transmission and photoluminescence (PL) spectra. 相似文献
10.
Z.Q. Wu J.F. Tang J.H. HuangX.H. Gong Y.J. ChenY.F. Lin Z.D. LuoY.D. Huang 《Optical Materials》2011,34(1):287-291
Trivalent thulium-doped K5Bi(MoO4)4 single crystals were grown by the Czochralski method. Its polarized absorption and fluorescence spectra and fluorescence decay curves were recorded at room temperature. On the basis of the Judd-Ofelt theory, the spectral parameters of the Tm3+:K5Bi(MoO4)4 crystal were calculated. The cross relaxations between Tm3+ ions were analyzed. The emission cross sections of the 3F4 → 3H6 transition were obtained by the Fuchtbauer-Ladenburg formula and then the gain cross sections around 1.9 μm were calculated. The peak emission cross section and width of emission band around 1.9 μm are comparable to those for Tm3+:YAG and the tunable range is about 280 nm for the potential ∼1.9 μm laser operation via the 3F4 → 3H6 transition. 相似文献
11.
We report, for the first time to our knowledge, the formation of single mode planar waveguide in z-cut YVO4 by 400 keV, 500 keV He ion implantation in fluence of 3 × 1016 ions/cm2 at room temperature or at liquid nitrogen temperature (77 K). We investigated annealing behavior of the guiding mode and near-field image in the waveguide by prism-coupling method and end-face coupling method respectively. We found that the effective refractive index of the TE0 mode was different before and after annealing for the samples implanted at room temperature, while, annealing had nearly no influence on the effective refractive index of the TE0 mode of the samples implanted at liquid nitrogen temperature (77 K). After annealing at 600 K for 1 h, no guiding mode was observed in the sample implanted by 400 keV He ion in fluence of 3 × 1016 ions/cm2 at room temperature. The Rutherford backscattering/channeling technique was used to investigate the damage reduction after annealing treatments. The minimum yield of the implanted, annealed sample was 5.43%. We reconstructed the refractive index profiles in the waveguide under different condition by applying intensity calculation method. 相似文献
12.
G. Aka E. Reino P. Loiseau D. Vivien B. Ferrand L. Fulbert D. Pelenc G. Lucas-Leclin Patrick Georges 《Optical Materials》2004,26(4):431-436
We have taken advantage of congruent melting behavior of the nonlinear rare-earth oxoborate Ca4REO(BO3)3 family to perfect a process of collective fabrication of self-frequency doubling microchip laser based on Nd:GdCOB (Ca4Gd1−xNdxO(BO3)3) crystals. The process goes from Czochralski boule to 1 × 3 mm2 chips perfectly oriented (better than 0.1°) to the phase matching direction (θ=90°, φ=46°) in the XY principal plane, with dielectric mirrors directly deposited on both faces of the chips. 20 mW of self-frequency doubling output power at 530 nm was performed under 800 mW of diode laser as incident pump power at 812 nm. In addition, new compositions from the solid solution Ca4Gd1−xYxO(BO3)3 (Gd1−xYxCOB) (x=0.13, 0.16, 0.44) have been grown by the Czochralski pulling method, in order to achieve noncritical phase matching (NCPM) second harmonic generation of 4F3/2 → 4I9/2 Nd3+ doped laser hosts. Three types of laser wavelengths have been chosen: Nd:YAP (YAlO3) at 930 nm, Nd:YAG (Y3Al5O12) at 946 nm, and Nd:ASL (NdySr1−x Lax−yMgx Al12−xO19) at 900 nm. Angular acceptance measurements of these three types of compositions present very large values, compared to pure GdCOB or YCOB oriented in critical phase matching configurations. 相似文献
13.
C.H. Cheng X.H. GongY.F. Lin Z.D. LuoY.J. Chen J.H. HuangY.D. Huang 《Optical Materials》2011,33(6):763-767
A Ho3+-doped NaLa(MoO4)2 single crystal was grown by the Czochralski method. The polarized absorption spectra, polarized fluorescence spectra, and fluorescence decay curves of the crystal were measured at room temperature. The spontaneous emission probabilities, radiative lifetimes, and fluorescence branching ratios of the typical fluorescence multiplets of Ho3+ ions were calculated. The polarized stimulated emission and gain cross-sections of the 5I7 → 5I8 transition were obtained. The results show that the Ho3+:NaLa(MoO4)2 crystal is a promising gain medium for tunable and ultrashort pulse lasers operating around 2.0 μm. 相似文献
14.
This work is focused on spectral investigations of Tm3+ doped Sc2O3 transparent ceramic as potential material for diode-pumped solid-state laser emitting around 2 μm. In the context of the Judd-Ofelt (J-O) theory a series of spectroscopic parameters such as J-O intensity parameters, oscillator strengths, radiative transitions probabilities, and radiative lifetimes as well as branching ratios are evaluated. The gain cross-sections which lead to an estimation of the probable operating laser wavelength for the 3F4 → 3H6 Tm3+ laser transition were also calculated. 相似文献
15.
Highly transparent YVO4:Eu thin films were deposited via dip coating of liquid nanoparticle dispersions on glass substrates. Annealing of the nanoparticle layers resulted in restructuring of the material into oriented crystalline films. The crystallinity was confirmed using powder X-ray diffraction. Film thickness was adjusted to 467 nm by multiple deposition. The resulting coatings show > 99% absorbance for wavelength below 300 nm and > 90% transmission in the visible spectral range. Under UV-light excitation a bright red photoluminescence with a quantum efficiency of 20% is observed. A planar, transparent dielectric barrier discharge lamp was constructed using YVO4:Eu coated glasses and transparent electrodes made from antimony-doped tin dioxide thin films. 相似文献
16.
E. van der Kolk O.M. Ten KateJ.W. Wiegman D. BinerK.W. Krämer 《Optical Materials》2011,33(7):1024-1027
A high resolution luminescence study of NaLaF4: 1%Pr3+, 5%Yb3+ and NaLaF4: 1%Ce3+, 5%Yb3+ in the UV to NIR spectral range using a InGaAs detector and a fourier transform interferometer is reported. Although the Pr3+(3P0 → 1G4), Yb3+(2F7/2 → 2F5/2) energy transfer step takes place, significant Pr3+1G4 emission around 993, 1330 and 1850 nm is observed. No experimental proof for the second energy transfer step in the down-conversion process between Pr3+ and Yb3+ can be given. In the case of NaLaF4: Ce3+, Yb3+ it is concluded that the observed Yb3+ emission upon Ce3+ 5d excitation is the result of a charge transfer process instead of down-conversion. 相似文献
17.
B.T. Zhang H.T. Huang J.L. He J.F. Yang J.L. Xu C.H. Zuo S. Zhao 《Optical Materials》2009,31(11):1697-1700
In this paper, the output performances at 1.34 μm in continuous wave operation and passive Q-switching regime of a diode-end-pumped Nd:Gd0.5Y0.5VO4 laser have been investigated. The passive Q-switching regime was achieved with Co2+:LaMgAl11O19 (Co2+:LMA) saturable absorbers crystals. A maximum average output power of 230 mW was recorded with a Co2+:LMA with initial transmission of 81%. The minimum pulse duration was 116 ns, which corresponded to a repetition rate of 360 kHz, the single pulse energy of 2.1 μJ and the pulse peak power of 5.5 W. 相似文献
18.
D. Kasprowicz M.G. BrikA. Majchrowski E. MichalskiP. G?uchowski 《Optical Materials》2011,33(11):1595-1601
Triply-doped single crystals KGd(WO4)2:Er3+/Yb3+/Tm3+, KGd(WO4)2:Tb3+/Yb3+/Tm3+ and KGd(WO4)2:Pr3+/Yb3+/Tm3+ were grown by the Top Seeded Solution Growth (TSSG) method, with an aim of getting efficient up-converted multicolored luminescence, which subsequently can be used for generation of white light. Such an aim determined the choice of the triply doped compounds: excitation of the Yb3+ ions in the infrared spectral region is followed by red, green and blue emission from other dopants. It was shown that all these systems exhibit multicolor up-conversion fluorescence under 980 nm laser irradiation. Detailed spectroscopic studies of their absorption and luminescence spectra were performed. From the analysis of the dependence of the intensity of fluorescence on the excitation power the conclusion was made about significant role played by the host’s conduction band and other possible defects of the KGd(WO4)2 crystal lattice in the up-conversion processes. 相似文献
19.
The vacuum ultraviolet excited luminescent properties of Eu3+, Tb3+, Dy3+, Sm3+ and Tm3+ in the matrices of Ca4Y6(SiO4)6O were investigated. The bands at about 173 nm in the vacuum ultraviolet excited spectra were attributed to host lattice absorption of the matrix Ca4Y6(SiO4)6O. For Eu3+-doped samples, the O2− → Eu3+ CTB was identified at 258 nm. Typical 4f-5d absorption bands in the region of 195-300 nm were observed in Tb3+-doped samples. For Dy3+-doped and Sm3+-doped samples, the broad excitation bands consisted of host absorptions, CTB and f-d transition. For Tm3+-doped samples, the O2− → Tm3+ CTB was located at 191 nm. About the color purity and emission intensity, Ca4Y6(SiO4)6O:Tb3+ is an attractive candidate of green light PDP phosphor, and Ca4Y6(SiO4)6O:Dy3+ has potential application in the field of mercury-free lamps. 相似文献
20.
Passive Q-switching laser operation of Nd:GdxY1−xVO4 mixed crystals at 671 nm has been compared in the same V-shape folded cavity. Based on our comparative analysis, the best laser characteristics - the highest pulse energy and peak power and the shortest pulse width - were demonstrated by Nd:Gd0.63Y0.37VO4 crystal. At the same time, this crystal possesses the lowest thermal conductivity in comparison with the other Nd:GdxY1−xVO4 crystals, which could result in decreasing the average laser output power. To verify this assumption we also measured the focal lengths of thermal lens induced in the crystals during the laser operation. 相似文献