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固体材料的激光制冷是近年来发展起来的一个新的研究领域. 掺Tm3+的ZrF4-BaF2-LaF3-AlF3-NaF-PbF2(ZBLANP)玻璃材料是激光冷却的典型材料之一. 与另一种制冷掺杂离子Yb3+相比,Tm3+具有更好的制冷潜力. 目前制约材料制冷的一个主要机理就是荧光再吸收. 首先根据Tm3+:ZBLANP的光谱参数,利用半经典的随机行走模型得到了不同情况下的平均荧光再吸收次数,随后分析了荧光光子界面出射的全反射效应,并对所得结果进行了修正. 计算结果表明,荧光再吸收会导致量子效率降低0.5%-1%,出射荧光波长红移达到2-10 nm,激光制冷的效率和功率降低. 为了有利于荧光出射和净制冷的实现, 宜采用小体积细长棒的制冷元.
关键词:
激光制冷
稀土离子
荧光再吸收 相似文献
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采用改进的化学气相沉积工艺结合溶液掺杂法制备了掺Tm3+石英光纤预制棒,并拉制成纤芯/包层尺寸约为25/400μm的双包层掺Tm3+光纤,通过电子探针显微分析测得其中Tm2O3和Al2O3的浓度分别为2.6 wt%和1.01 wt%,在793 nm处测得的包层吸收为3 dB/m.基于上述大模场掺Tm3+光纤,搭建了一个高功率全光纤主振荡功率放大结构的掺Tm3+光纤激光器,窄线宽掺Tm3+种子源经过一级放大后,最高输出功率达到530 W,对应的斜率效率为50%,输出激光的中心波长为1980.89 nm.实验中没有观察到明显的放大自发辐射和非线性效应,输出功率仅受限于抽运功率.该结果为目前国内2μm波段全光纤结构激光器实现的最高输出功率,验证了国产掺Tm3+石英光纤在高功率系统中的可靠性. 相似文献
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制备了70TeO2-20WO2-10ZnO-xTm2O3系统玻璃,根据所测玻璃的吸收光谱,应用Judd-Ofelt(J-O)理论计算出Tm3+离子在碲酸盐玻璃的J-O强度参数、Tm3+在玻璃中的自发辐射概率A、荧光分支比β及荧光辐射寿命 τR 等各项光谱参数.测定了玻璃的荧光光谱,并计算了Tm3+在碲酸盐玻璃中的荧光有效线宽、峰值受激发射截 面.比较了Tm3+在不同掺杂浓度下的光谱特性,认为当Tm2O3掺杂浓度达到 0.8wt%—1wt%时,所获得的荧光强度与荧光线宽达到最佳值,掺Tm3+ 碲酸盐玻璃是一种理想的S波段宽带光纤放大器用基质材料.
关键词:
碲酸盐玻璃
宽带光纤放大器
荧光线宽
荧光峰值发射截面 相似文献
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制备了高折射率Tm3+/Yb3+共掺杂铋碲酸盐玻璃,利用棱镜耦合法测量出玻璃在632.8和1550nm波长处的折射率分别为2.0365和1.9795. 对玻璃的吸收、荧光和红外透过光谱展开了测试与分析,根据Judd-Ofelt理论对吸收光谱进行拟合,求得Tm3+的振子强度参数Ωt(t=2,4,6)分别为3.90×10-20, 2.03×10-20和9.03×10-2
关键词:
3+/Yb3+共掺')" href="#">Tm3+/Yb3+共掺
铋碲酸盐玻璃
光谱参数
上转换荧光 相似文献
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制备了不同Tm3+离子浓度的PbO-Bi2O3-Ga2O3-GeO2重金属氧化物玻璃,根据吸收光谱计算了JO强度参量以及Tm3+离子在玻璃中的自发辐射概率、荧光分支比及荧光辐射寿命等光谱参数.通过测量1470nm波段发射光谱,计算表明该玻璃系统在S波段有较宽的荧光半高宽和较大的峰值受激发射截面,但玻璃中荧光寿命随稀土离子浓度增加呈线性下降,而交叉弛豫速率随浓度的平方迅速增加.研究结果仍可表明掺铥重金属氧化物玻璃是一种理想的S波段宽带光纤放大器用基质材料.
关键词:
重金属氧化物玻璃
3+离子')" href="#">Tm3+离子
S波段光纤放大器
光谱性质 相似文献
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在MCVD车床上利用“湿法”掺杂方法研制出纤芯高掺Ge的石英基掺Tm3+光纤预制棒,采用侧面研磨和抛光工艺制成横截面为正六边形的光纤预制棒.经拉丝,内层涂覆低折射率材料后制成包层抽运光纤.测试其吸收谱,并对光纤参数进行优化.通过在光纤两端紫外写入光纤Bragg光栅,制成线形光学谐振腔,在工作波长793nm的激光抽运下,获得工作波长1947.1031nm、功率2.05W的激光输出.由此证明这种光纤具有优异的光学特性.
关键词:
3+光纤')" href="#">石英基掺Tm3+光纤
光纤Bragg光栅
包层抽运
光纤激光器 相似文献
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报道了Tm3+/Ho3+共掺的镓铋酸盐玻璃14Ga2O3-25Bi2O3-20GeO2-31PbO-10PbF2玻璃1.47μm(S波段)发光和能量传递特征,应用Judd-Ofelt理论计算了玻璃的强度参数Ωt(t=2,4,6),自发辐射概率A、荧光分支比β,荧光辐射寿命τ等各项光谱参数以及有效荧光线宽Δλeff和峰值发射截面σpeake.通过测量荧光光谱和荧光寿命研究了Ho3+离子掺杂浓度对Tm3+离子1.47μm波段发光性能的影响,分析了Tm3+和Ho3+之间的能量传递过程.结果表明一定浓度内Ho3+的共掺迅速降低了Tm3+:3F4能级的粒子数,而对3H4能级粒子数影响不大,从而降低了3F4和3H4能级间布居数反转的难度,极大地提高了1.47μm发光效率.研究表明镓铋酸盐玻璃是适用于S波段光纤放大器的一种潜在基质材料,而掺杂一定浓度的Ho3+离子有利于提高Tm3+离子在1.47μm波段的发光效率.
关键词:
重金属氧化物玻璃
光谱性质
3+/Ho3+离子')" href="#">Tm3+/Ho3+离子
能量传递 相似文献
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We propose a theoretical model for an optimized fiber structure for use in anti-Stokes laser cooling of solids. The sample is an optical fiber fabricated from a fluorozirconate glass ZBLANP with a core doped with Yb(3+) ions. The diameter of the fiber core is optimized to achieve the largest temperature change in the sample. It is shown that for each value of the pump power there is an optimized diameter of the fiber core, which permits the largest drop in the temperature of the sample. 相似文献
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High near-infrared transparency Tm3+-doped germanate bulk glass and fiber have been fabricated and 2 μm emission properties demonstrated. Energy-transfer processes
in the germanate glass and fiber are discussed. The emission spectra are obtained from both bulk glass and fiber with the
excitation of a 794 nm laser diode. The results indicate that the line width of the Tm3+:3F4→3H6 emission spectra measured in fibers is narrower than that of the bulk glass sample and shifts to longer wavelengths with
increment of fiber length. The extended overlap integral method is used to calculate the microparameters of energy transfer
and critical distance. A model is derived to better understand of the energy-transfer process of thulium ions in the germanate
glasses responsible for emission at 2 μm. The study indicates that Tm3+-doped germanate fibers with a large core diameter has proved to be promising infrared optical and high-power level laser
materials. 相似文献
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The diode laser (LD) clad-pumped 1947.6 nm continuous wave (CW) Tm3+-doped fiber amplifier is reported using the master oscillation power amplifier (MOPA) method. The injected seed laser is
provided by an all-fiber LD-clad-pumped Tm3+-doped single-mode fiber laser, which has a nearly 2.4 W maximal output power and 0.1 nm ultra-narrow linewidth based on the
intracore reflection FBG. Using the 25/400 μm double-clad LMA Tm3+-doped fiber as the gain fiber, the output maximal output power is 30.6 W from the fiber amplifier, with a slope efficiency
of 39.1% respected to the LD total output power. A high power multi-mode fiber combiner is used to couple high power LD light
into the gain fiber. The output wavelength is also located at 1947.6 nm, with the slightly expanded laser linewidth of 0.2
nm. 相似文献
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The top-hat beam clad-pumped Tm3+-doped fiber laser was realized simply using an intracavity multi-mode abrupt taper. The ratio of the flat-top diameter to
the spot diameter reaches 53%, with a small intensity variation less than 6%, and the top-hat beam’s half-divergence angle
is only 5.3°. The fiber laser has a maximal output power of 5 W with slope efficiency of 39.7%, pumped by the 792 nm diode
laser (LD). The abrupt taper is directly made on the multi-mode double-clad Tm3+-doped fiber near the fiber laser output end with the 0.45 ratio of taper waist diameter to fiber clad diameter, and this
fiber end 4% Fresnel reflection is used to be the output coupler. The fiber laser’s high reflective coupler is an intracore
multi-mode FBG, which is directly written into the multi-mode Tm3+-doped fiber core using femtosecond laser and phase mask, at the other fiber end. The abrupt taper has no obviously influence
on the fiber laser output power, and the output laser spectrum. 相似文献
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L. A. Nurtdinova V. V. Semashko A. K. Naumov R. Yu. Abdulsabirov S. L. Korableva 《Physics of the Solid State》2005,47(8):1463-1466
The results of spectral kinetic studies of several fluoride crystals activated by Yb3+ and Tm3+ ions are presented, and their possible application as cooling elements of optical refrigerators is discussed. Optimum excitation conditions for the laser cooling effect in these crystals are found. The cooling efficiency is established to depend on the degree of order in the active medium. 相似文献
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Tm3+/Yb3+ codoped tellurite glass has been prepared. Density, refractive index, optical absorption, Judd-Ofelt parameters and spontaneous
transition probabilities of Tm3+ have been measured and calculated, respectively. Intense blue three-photon upconversion fluorescence and S-band (1470 nm)
fluorescence were investigated under the excitation of a 980 nm diode laser at room temperature. Judd-Ofelt parameters, strong
blue three-photon upcoversion emission of Tm3+ in glass indicate that Tm3+/Yb3+ codoped tellurite glass is a promising blue color upconversion optical and laser material. In addition, experiment results
showed the 980 nm laser was more efficient than 808 nm laser when pumping Tm3+/Yb3+ codoped tellurite glass, Tm3+/Yb3+ codoped tellurite glass also could be a promising material for S-band amplification. 相似文献
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In this work, CW laser operation of Tm3+-doped LiNbO3 channel waveguides has been modelled. The model is based on time dependent laser rate equations coupled with the laser signal and pump photon flux equations. Steady state solutions for the population densities, pump and signal powers are obtained by using finite difference discretization of the active volume. The effects of spectroscopic parameters such as concentration dependent cross-relaxation and excess waveguide loss have been analyzed. We demonstrate good agreement with experimental data previously reported in Zn-diffused LiNbO3:Tm3+ channel waveguide lasers. It is shown also that laser performance can be substantially improved by optimizing the cavity length. 相似文献
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We propose a laser-diode-pumped Yb:YAG laser as a novel practical fiber amplifier pump source, and describe its first successful
application of high-output-power operation (850 mW=+29.3 dB m) of an Er3+,Yb3+-codoped fiber amplifier at 1.55 μm. We have developed both bulk and microchip Yb:YAG lasers and obtained 3.3 W and 2.7 W,
respectively, in the cw mode at room temperature. Laser-diode-pumped Yb:YAG lasers are shown to have a potential applicability
to such fiber amplifiers as Pr3+-doped amplifiers and Tm3+-doped amplifiers, as well as Er3+,Yb3+-codoped fiber amplifiers.
Received: 12 August 1999 / Revised version: 3 September 1999 / Published online: 20 October 1999 相似文献