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1.
Er3+ and Tm3+ singly doped and codoped new fluoride glasses were prepared by traditional melt-quenching method. Efficient 3 μm emission was obtained under 980 nm laser excitation. It is worthy to notice that one of the two ions can be the sensitizer to the other one by depressing the Er3+: 1.5 μm emission through the energy transfer process from Er3+:4I13/2 level to Tm3+:3F4 level. On the basis of measured absorption spectra, the Judd-Ofelt intensity parameters and radiation emission probability were calculated to evaluate the spectroscopic properties. Additionally, the micro-parameters together with the phonon assistance of Er3+:4I13/2 → Tm3+:3F4 and Er3+:4I11/2 → Tm3+:3H5 processes were quantitatively analyzed by using Dexter model. The theoretical micro-parameters results meet well with the experiments which indicates that Er3+/Tm3+ codoped fluoride glass is a potential kind laser glass for 3 μm laser. 相似文献
2.
2.0 mol% (relative to Ba2+) Yb3+ doped α-BaB2O4 (α-BBO) crystal was obtained by the Czochralski method. The doped crystal structure was determined by means of an X-ray diffraction analysis. The absorption, near-infrared (NIR) luminescence spectra and fluorescence decay curve of Yb3+ doped α-BBO crystal were investigated. NIR emission under 940 nm and 980 nm LDs (laser diodes) excitation was observed in the Yb doped α-BBO crystal. 相似文献
3.
Meng Wang Lixia Yi Guonian Wang Lili Hu Junjie Zhang 《Solid State Communications》2009,149(29-30):1216-1220
The spectroscopic properties and energy transfer mechanisms in Ho3+ doped fluorophosphate glasses sensitized by Er3+ and Tm3+ at the 2 μm region are investigated. The absorption spectra and fluorescence spectra of the Tm–Ho doubly-doped glass system and Er–Tm–Ho triply-doped glass system are measured. According to the absorption spectra, the Judd–Ofelt parameters and spontaneous transition probability are calculated and compared with those of other glass hosts. From the fluorescence spectra, the fluorescence intensity of Er–Tm–Ho glass system at 2.0 μm is 0.95 and larger than that of the Tm–Ho glass system, which is 0.69. Meanwhile, the 2.0 μm to 1.8 μm and 2.0 μm to 1.53 μm peak intensity ratios in the Er–Tm–Ho glass system are 8.63 and 22.79, respectively, suggesting sufficient energy transfer between Er3+, Tm3+ and Ho3+ ions. In addition, the pumping schemes and energy transfer mechanisms of Tm–Ho doubly-doped and Er–Tm–Ho triply-doped glasses are discussed. The study indicates that the Er–Tm–Ho triply-doped glass system is a significant sensitized way pumped at 800 nm in fluorophosphate glasses for 2 μm applications. 相似文献
4.
A.-H. Li Z.-R. Zheng T.-Q. Lü L. Sun W.-L. Liu W.-Z. Wu 《Applied physics. B, Lasers and optics》2010,98(1):149-158
Four near-stoichiometric lithium niobate (NSLN) crystals codoped with Er3+ (1 mol%) and MgO (0, 0.5, 1.0, and 2.0 mol%) were grown from K2O-based flux in air using top seeded solution growth technique. The [Li]/[Nb] ratio, estimated from the blueshift of ultraviolet
absorption edge, is 97.2% in NSLN:Er. MgO; codoping can increase the segregation coefficient of Er3+ in NSLN:Er:MgO crystal. The photorefractive damage threshold is enhanced by three orders of magnitude for NSLN:Er codoped
with 1 mol% MgO, it coincides with the peak shift of OH− absorption spectrum from 3481 to 3535 cm−1. Judd–Ofelt theory based on absorption spectra is used to analyze the influence of MgO concentration on the Judd–Ofelt intensity
parameter, transition strength, fluorescence branching ratio, and stimulated emission cross section. From the time-resolved
emission spectra and the comparison among emission spectra, two Er3+ crystal-field sites are ascertained in NSLN:Er codoped with 2 mol% MgO, this coincides with the bimodal structure in X-ray
photoelectron spectrometry spectra. The upconversion processes under pulse excitation is proposed based on the pump energy
dependence and decay kinetics. The distribution of Er3+-clustered sites in NSLN:Er:MgO series is discussed based on the nonexponential decay curves monitored at 550 nm under two-photon
excitation. 相似文献
5.
For Nd:LaxY1−xVO4 (x = 0.11) crystal, the 4F3/2 → 4I13/2 transition property was investigated for the first time. The fluorescence peak of Nd:La0.11Y0.89VO4 crystal exhibited obvious inhomogeneous broadening comparing with that of Nd:YVO4 crystal. With laser diode array as pump source, 1.34 μm continuous-wave (CW) and active Q-switched laser operations based on 4F3/2 → 4I13/2 transition were realized. For CW laser operation, the maximum output power of 2.47, 2.13 W is obtained with slope efficiencies of 29.4%, 27.6%, and optical to optical conversion efficiency of 26.2%, 24.7%, respectively for a, c cut crystal samples. For acousto-optic (AO) Q-switched laser operation, the shortest pulse width, highest peak power and maximum pulse energy came from the a-cut sample, which were 13 ns, 2.69 kW and 35 μJ, respectively. 相似文献
6.
We report the first demonstration, to our knowledge, of passive Q-switched mode-locking in a Tm3+:YAP laser, operating in the 2 μm broadly spectral region formed with a compact Z-flod cavity. A transmission-type single-walled carbon nanotube saturable absorber (SWCNT–SA) is used for the initiation of the pulse generation. The repetition rate of the Q-switched envelope was 60 kHz at the pump power of 8.6 W. The mode-locked pulses inside the Q-switched pulse envelope had a repetition rate of ~92 MHz. A maximum average output power of 761 mW was obtained. The dependence of the operational parameters on the pump power was also investigated experimentally. 相似文献
7.
A. Labate N. R. Heckenberg R. Meucci M. Ciofini 《Applied physics. B, Lasers and optics》1993,56(5):307-311
Measurements of the pressure dependence of the relaxation rate of vibrationally excited molecules in the 119 m CH3OH laser have been correlated with the pressure and pump power dependence of the output power in the framework of a rate-equation model for which numerical and approximate analytical solutions have been obtained. Both diffusion and collisional de-excitation are important, and substantial deviations from thermal equilibrium populations are deduced, consistent with an operating pressure range which increases with pump power. 相似文献
8.
Optical properties of a Ho-doped LaF3 single crystal have been detailed investigated as a promising material for 2 μm and 2.9 μm lasers for the first time. Judd–Ofelt theory was applied to analyze the absorption spectrum to determine the J–O intensity parameters Ωt(t=2,4,6), based on which the emission probabilities, branching ratio and radiative lifetime for the as-grown crystal were all calculated. The stimulated emission cross-sections of the 5I7 → 5I8 and 5I6 → 5I7 transitions were obtained by using the Fuchtbauer–Ladenburg method. The gain cross-section for 2 μm emission becomes positive once the population inversion level reaches 30%. The Ho:LaF3 crystal shows long fluorescence lifetime of 5I7 manifold (25.81 ms) as well as 5I6 manifold (10.37 ms) compared with other Ho3+-doped crystals. It can be proposed that the Ho:LaF3 crystal may be a promising material for 2 μm and 2.9 μm laser applications. 相似文献
9.
Ilya Mingareev Fabian Weirauch Alexander Olowinsky Lawrence Shah Pankaj Kadwani Martin Richardson 《Optics & Laser Technology》2012,44(7):2095-2099
Absorber-free transmission and butt-welding of different polymers were performed using thulium fiber laser radiation at the wavelength 2 μm. The relations between the laser process conditions and the dimensions and quality of the seam were investigated by means of optical and phase-contrast microscopy. Mechanical properties of the weld joints were studied in tensile strength tests. Laser-welded polyethylene samples revealed a tensile strength of greater than 80% of the bulk material strength. Transmission welding of different polymer combinations featured the formation of different joint classes depending on the spectral properties. The experiments demonstrate new application areas of mid-IR fiber laser sources for materials processing. 相似文献
10.
Important for telecommunications, luminescence of trivalent erbium (Er) at 1.5 μm generally arises from a Stokes-shifted downconversion mechanism. We show that this luminescence following direct excitation of the 4I11/2 state is generated by upconversion-mediated looping process in Er3+/Sc3+-codoped LiNbO3 single crystal. Emissions at 1.0 and 1.5 μm from the 4I11/2 and 4I13/2 states display linear and quadratic dependences on the excitation density in two separated ranges with a threshold of 20 W/cm2. This observation correlates with two- and four-photon processes in green and red upconversion emissions. The mechanism described has implications in the improvement of the output of 1.5 μm luminescence. 相似文献
11.
12.
《Comptes Rendus Physique》2003,4(6):621-637
Laser diodes emitting at room temperature in continuous wave regime (CW) in the mid-infrared (2–5 μm spectral domain) are needed for applications such as high sensitivity gas analysis by tunable diode laser absorption spectroscopy (TDLAS) and environmental monitoring. Such semiconductor devices do not exist today, with the exception of type-I GaInAsSb/AlGaAsSb quantum well laser diodes which show excellent room temperature performance, but only in the 2.0–2.6 μm wavelength range. Beyond 2.6 μm, type-II GaInAsSb/GaSb QW lasers, type-III ‘W’ InAs/GaInSb lasers, and interband quantum cascade lasers employing the InAs/Ga(In)Sb/AlSb system, all based on GaSb substrate, are competitive technologies to reach the goal of room temperature CW operation. These different technologies are discussed in this paper. To cite this article: A. Joullié, P. Christol, C. R. Physique 4 (2003). 相似文献
13.
14.
Influences of Mg^2+ ion on dopant occupancy and upconversion luminescence of Ho^3+ ion in LiNbO3 crystal
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The effects of a Mg^2+ ion on the dopant occupancy and upconversion luminescence of a Ho^3+ ion in LiNbO3 crystal are reported. The birefringence gradient of the crystal is measured to investigate the optical homogeneity. The X-ray powder diffraction spectrum and the upconversion luminescence are used to investigate defect structure and spectroscopic properties of Mg,Ho:LiNbO3. Under 808-nm excitation, blue, red, and very intense yellow-green bands are observed. Based on the energy levels of Ho^3+ in LiNbO3, and the pump intensity dependence of the observed emission, an excitation scheme is presented. The upconversion emission spectra reveal an enhancement of upconversion intensity when the Mg^2+ ions are introduced into Ho:LiNbO3. The main upconversion mechanism is discussed in this work. 相似文献
15.
It is proposed for the first time that the 1.5 μm Er3+ photoluminescence peak may be significantly broadened by a photonic crystal microcavity structure. Two coupled microcavities
have been designed and prepared by sol-gel processing based on alternating layers of silicate glass and titania materials.
The 1.5 μm emission spectra of the Er3+ ions embedded in these microcavity structures are measured and discussed. It is found that the spontaneous emission spectra
are effectively broadened to a point where they become approximately square in shape. The full width at half maximum (FWHM)
reached a value as large as 183 nm, which is the best result reported so far. The measured photoluminescence profiles agree
well with simulated curves and an intensity enhancement by the microcavities has also been observed. These results may be
of significance for applications requiring broadened or otherwise modified spontaneous emission spectra, such as application-specific
LEDs and other non-coherent light sources. The present technique can easily be applied to other active materials. 相似文献
16.
B.C. Jamalaiah T. Suhasini L. Rama Moorthy Il-Gon Kim Dong-Sun Yoo Kiwan Jang 《Journal of luminescence》2012,132(5):1144-1149
Trivalent neodymium doped multi-component lead borate titanate aluminumfluoride (LBTAFNd) glasses were prepared and characterized as a function of Nd3+ ions concentration through optical absorption, NIR luminescence and decay measurements. The intensity (Ω2,4,6) and other radiative parameters were determined within the frame work of Judd–Ofelt theory. The intensities of absorption bands were expressed in terms of experimental oscillator strengths. Reasonably small root mean square deviation of ±0.384×10?6 obtained between the experimental and calculated oscillator strengths indicates the validity of intensity parameters. Upon 805 nm laser excitation, the NIR emissions at 0.92 μm (4F3/2→4I9/2), 1.07 μm (4F3/2→4I11/2) and 1.35 μm (4F3/2→4I13/2) were observed. The spectroscopic quality factor has been determined from the Ω4 and Ω6 intensity parameters as well as the intensities of emission bands centered at 1.07 and 1.35 μm. The decay curves of the 4F3/2 excited state were recorded by monitoring the emission and excitation wavelengths at 1.07 μm and 805 nm, respectively. The decay curves exhibit single exponential behavior for all the glasses. The laser characteristic parameters of 4F3/2→4I11/2 (1.07 μm) transition were determined and compared with other reported glasses. 相似文献
17.
The influence of the thulium ion concentration on the 1.94-??m laser performance of c-cut Tm:YAP crystal was investigated in this paper. Three crystals with 3, 4, and 5% Tm3+ (atom concentration) were examined at 18°C. Our experimental results showed that, the best power performance was obtained with the 4% Tm:YAP crystal. By using 24.8 W of incident pump power at 795 nm, a maximum of 7.5 W of output power was obtained. The slope efficiency was 48.8%, corresponding to diode-to-Tm conversion efficiency of 30.2%. 相似文献
18.
A Tm3+-doped silicate glass (SiO2–CaO–Na2O–K2O) with good thermal stability is prepared by the melt-quenching method. Intense 1.8 μm emission is obtained when pumped by an 808 nm laser diode. Based on the measured absorption spectra, radiative properties are predicted using Judd–Ofelt theory and Judd–Ofelt parameters Ωλ (λ=2, 4, 6), as well as absorption and emission cross-sections are calculated and analyzed. The difference between the measured Tm3+:3F4 lifetime and the calculated lifetime is also discussed. The emission property together with good thermal property indicates that Tm3+-doped silicate glass is a potential kind of laser glass for efficient 2 μm laser. 相似文献
19.
用于1.5μm光波导放大器的高浓度Er3+掺杂玻璃 总被引:6,自引:0,他引:6
制备了用于 1.5μm光波导放大器高浓度掺杂 Er3 的氟铝酸盐、氟锆酸盐及磷酸盐玻璃。在 0 .80μm和 0 .98μm连续激光二极管激发下分析比较了这三种玻璃 1.5μm发射的光谱特性、浓度猝灭及其机制。研究表明 :由于在 0 .98μm激发下 ,激发态吸收较 0 .80μm激发下小得多 ,因而其 1.5μm荧光发射量子效率也比 0 .80μm激发下高得多 ;氟铝酸盐玻璃具有最大的荧光强度和最小的浓度猝灭效应 ,是理想的 1.5μm光波导放大器基质玻璃材料 相似文献
20.
N. N. Il’ichev P. V. Shapkin E. S. Gulyamova A. V. Kir’yanov A. S. Nasibov 《Laser Physics》2010,20(5):1091-1094
Effective lasing is obtained in the transversely pumped ZnSe single crystals that are doped with Cr2+ ions using diffusion methods. A Q-switched Er3+-doped glass laser with a radiation wavelength of 1.54 μm is used for pumping. The resulting laser energy is 150 μJ at an
absorbed pump energy of 600 μJ, so that the efficiency is 25% and the slope efficiency is 29%. An increase in the gain (up
to the superluminescence level) due to the application of the transverse pumping of the active element with a substantially
non-uniform distribution of the dopant is discussed. 相似文献