Preparation and laser properties of Yb^3＋-doped microstructure fiber based on hydrolysis-melting technique

The Yb^(3+)-doped silica glass was prepared by the Si Cl_4 hydrolysis doping and powder melting technology based on high frequency plasma. The absorption and emission characteristics of the Yb^(3+)-doped silica glass are studied at room temperature. The integrated absorption cross section,stimulated emission cross section and fluorescence lifetime are calculated to be 8.56×10~4 pm^3,1.39 pm^2 and 0.56 ms,respectively. The Yb^(3+)-doped microstructure fiber(MSF) was also fabricated by using the Yb^(3+)-doped silica glass as fiber core. What's more,the laser properties of the Yb^(3+)-doped MSF are studied.

Spectral and laser properties of Yb and Ho co-doped(YLa)_2O_3 transparent ceramic

Highly transparent Yb,Ho doped（YLa）2O3 ceramic was fabricated by conventional ceramic processing with nanopowders.The absorption and emission spectra of the ceramic was investigated.The energy transfer mechanism between Yb3＋ and Ho3＋ was also discussed.The strong emission band around 2 μm indicated that the Yb-Ho：（Y 0.90 La 0.10）2O3 transparent ceramic is a promising gain medium for the generation of 2 μm laser emissions.The laser operation of Yb-Ho co-doped（YLa）2O3 ceramic at 2.1 μm is first reported.

Investigation on Structures and Properties of Yb^(3+)-Doped Laser Glasses

The Yb3^＋ -doped silicate, phosphate and borophosphate laser glasses were prepared by means of conventional melt quenching technology. The physical and spectral properties of the glasses were investigated. The results show that, due to the existence of OH^-, the fluorescence lifetime of phosphate glass is shorter than that of silicate glass, so silicate glass has better spectral properties than phosphate glass. Silicate glass has better mechanical and thermal properties than phosphate glass, but with the addition of B2O3, mechanical and thermal properties of phosphate glass are improved greatly without fluorescence quenching effect. This kind of borophosphate glass can be used in high average power solid state lasers.

Spectral and Lasing Properties of Er^(3+0/Yb^(3+) Co-Doped Phosphate Glasses Pumped by LD

Er^3 ＋/Yb^3 ＋ phosphate glasses were fabricated. According to McCumber theory, the stimulated emission cross-section of Er^3＋ ions at 1533 nm was calculated on the basis of absorption spectrum, and 0.84 × 10^-20 cm^2 is derived, the fluorescence lifetime of ^4I13/2 level is 8.5 ms. An Er^3＋/Yb^3＋ co-doped phosphate glass CW laser pumped by LD was demonstrated at room temperature. The maximum output power is 80 mW and slope efficiency is 16.5%.

Pr,Yb,Ho:GdScO_(3)晶体生长及光谱性能

2.7-3.0μm波段激光在很多领域具有重要应用,为探索和发展该波段新型晶体材料,本文采用提拉法生长出Pr,Yb,Ho:GdScO_(3)晶体,通过共掺入Pr3+离子以达到衰减Ho^(3+):^(5)I_(7)能级寿命的目的.采用X射线衍射测试得到了晶体的粉末衍射数据,测量了拉曼光谱,并对晶体的拉曼振动峰进行指认,对Pr,Yb,Ho:GdScO_(3)晶体的透过光谱、发射光谱和荧光寿命进行表征.Yb^(3+)的最强吸收峰在966 nm,吸收峰半峰宽为90 nm;2.7-3.0μm波段最强发射峰在2850 nm,半峰宽为70 nm;Ho^(3+):^(5)I_(6)和^(5)I_(7)能级寿命分别为1094μs和56μs.与Yb,Ho:GdScO_(3)晶体相比,Yb^(3+)的吸收峰和2.7-3.0μm的发射峰半峰宽明显展宽,同时下能级寿命显著减小,计算表明Ho^(3+):^(5)I_(7)与Pr^(3+):^(3)F_(2)+^(3)H_(6)能级之间能实现高效的能量传递.以上结果表明Pr,Yb,Ho:GdScO_(3)晶体是性能更优异的2.7-3.0μm波段激光材料.

水平定向结晶法生长浓度渐变Yb∶YAG激光晶体及光谱性能研究

本文采用水平定向结晶(HDC)法成功生长出180 mm×81 mm×16 mm的浓度渐变Yb∶YAG激光晶体,从放肩部位和尾部分别获取了尺寸为40 mm×40 mm×7 mm、70 mm×70 mm×7 mm的Yb∶YAG激光晶体板条各两件。采用632 nm激光、偏光应力仪对晶体板条的光学性质进行检测,实验结果发现靠近晶坯自由表面的板条内部通透,无散射光路,应力较小且分布均匀,表明该晶体板条具有优异的光学质量。进一步测试分析了晶体板条不同位置处的吸收光谱,根据935 nm波长处的吸收系数计算出Yb^(3+)的掺杂浓度,发现40 mm×40 mm×7 mm的激光晶体板条中Yb^(3+)掺杂浓度沿晶体生长方向逐步增加,浓度梯度约为0.42%/cm;而70 mm×70 mm×7 mm的激光晶体板条中Yb^(3+)掺杂浓度几乎保持不变,约为4.50%。

Er^(3+),Yb^(3+)∶Ba_(3)Gd(PO_(4))_(3)晶体的生长、光谱和1.5μm激光性能

采用提拉法生长了1.85%Er,23.95%Yb∶Ba_(3)Gd(PO_(4))_(3)和1.95%Er,55.73%Yb∶Ba_(3)Gd(PO_(4))_(3)两种晶体(式中Er、Yb浓度为原子数分数)。测量并分析了晶体在室温下的吸收系数谱、上转换荧光谱、发射截面谱、增益截面谱和荧光衰减曲线。1.85%Er,23.95%Yb∶Ba_(3)Gd(PO_(4))_(3)晶体在峰值荧光波长1537 nm处的发射截面、Er^(3+)的4 I 13/2多重态荧光寿命和Yb^(3+)→Er^(3+)的能量传递效率分别为0.54×10^(-20)cm^(2)、9.9 ms和90%;1.95%Er,55.73%Yb∶Ba_(3)Gd(PO_(4))_(3)晶体在峰值荧光波长1537 nm处的发射截面、Er^(3+)的4 I 13/2多重态荧光寿命和Yb^(3+)→Er^(3+)的能量传递效率则分别为0.58×10^(-20)cm^(2)、9.7 ms和93%。基于975 nm半导体激光端面泵浦,在1.85%Er,23.95%Yb∶Ba_(3)Gd(PO_(4))_(3)晶体中实现了97 mW最高功率和27.1%斜效率的1567 nm连续激光输出,在1.95%Er,55.73%Yb∶Ba_(3)Gd(PO_(4))_(3)晶体中实现了93 mW最高功率和17.1%斜效率的1567 nm连续激光输出。

Yb,Ho∶GdScO_(3)晶体生长及光谱性能分析

采用提拉法生长出了尺寸为∅30 mm×50 mm的Yb,Ho∶GdScO_(3)晶体。通过X射线衍射得到了晶体的粉末衍射数据,使用GSAS软件进行了全谱拟合,得到了晶体的结构参数。测试了晶体的拉曼光谱,在100~700 cm^(-1)观察到18个拉曼振动峰。对Yb,Ho∶GdScO_(3)晶体的光谱特性进行了表征,并计算了Yb^(3+)的吸收截面,其在940、975 nm处的吸收截面分别为0.31×10^(-20)、0.42×10^(-20) cm^(2)。采用Judd-Ofelt理论计算了Ho^(3+)的跃迁强度参量Ω_(t),Ω_(4)/Ω_(6)值为2.04,并计算了辐射跃迁概率、能级寿命及荧光分支比等光谱参数。结果表明,Yb,Ho∶GdScO_(3)晶体的发光性能良好,是一种有前景的2~3μm激光晶体候选材料。

Yb∶YAG晶体荧光性能的调控研究

为了对Yb∶YAG晶体荧光性能进行调控以使其更好地应用于高能脉冲型激光器,结合密度泛函理论和晶体场理论,对掺杂调控后的Yb∶YAG晶体的电子结构、光谱学性质进行了理论计算,分析了不同粒子掺杂和占据格位情况下Yb∶YAG晶体的荧光性能,并在此基础上计算配方完成晶体生长实验、制备样品进行荧光性能测试验证。结果表明,通过以上过程掌握了Yb∶YAG晶体荧光寿命等参数的调控方法,共掺Cr后的Yb∶YAG荧光寿命可以从1.18 ms降低至0.94 ms。该研究为Yb∶YAG晶体实现高能脉冲激光应用奠定了理论和实验基础。

Yb∶CaGdAlO_(4)晶体及其超快激光技术研究进展

Yb∶CaGdAlO_(4)(简写为Yb∶CALGO)晶体具有部分无序的结构、优秀的热学和光谱性质、吸收发射带宽,适合采用商用高功率InGaAs二极管泵浦以实现高功率超快激光运转,其较高的非线性折射率系数有利于对锁模激光器的优化。该晶体还具有能级结构简单、本征量子缺陷低、辐射量子效率高等优点,是近年来新一代紧凑型、高效率、低成本激光二极管(LD)泵浦飞秒激光增益介质。本文简要介绍Yb∶CALGO的晶体结构、晶体生长、缺陷分析、热学性质和光谱性质等,并综合国内外学者近期的一些研究成果,重点综述了Yb∶CALGO晶体在半导体可饱和吸收镜、克尔透镜锁模的超快激光器及再生放大器超快激光技术中的最新研究进展。

Fabrication,microstructures,and optical properties of Yb:Lu_(2)O_(3) laser ceramics from co-precipitated nano-powders

The Yb:Lu_(2)O_(3)precursor made up of spherical particles was synthesized through the co-precipitation method in the water/ethanol solvent.The 5 at% Yb:Lu_(2)O_(3)powder is in the cubic phase after calcination at 1100℃ for 4 h.The powder also consists of spherical nanoparticles with the average particle and grain sizes of 96 and 49 nm,respectively.The average grain size of the pre-sintered ceramic sample is 526 nm and that of the sample by hot isostatic pressing grows to 612 nm.The 1.0 mm-thick sample has an in-line transmittance of 81.6%(theoretical value of 82.2%)at 1100 nm.The largest absorption cross-section at 976 nm is 0.96×1^(0-20)cm^(2) with the emission cross-section at 1033 nm of 0.92×10^(-20)cm^(2) and the gain cross sections are calculated with the smallest population inversion parameter β of 0.059.The highest slope efficiency of 68.7% with the optical efficiency of 65.1% is obtained at 1033.3 nm in quasi-continuous wave(QCW)pumping.In the case of continuous wave(CW)pumping,the highest slope efficiency is 61.0% with the optical efficiency of 54.1%.The obtained laser performance indicates that Yb:Lu_(2)O_(3)ceramics have excellent resistance to thermal load stresses,which shows great potential in high-power solid-state laser applications.

Anisotropy of the thermal and laser output properties in Yb,Nd:Sc_(2)SiO_(5) crystal

The anisotropy of thermal property in an Yb,Nd∶Sc_(2)SiO_(5) crystal is investigated from the temperature of 293 to 573 K. Based on the systematical study of thermal expansion, thermal diffusivity, and specific heat, the thermal conductivity in Yb,Nd∶Sc_(2)SiO_(5) crystals orientated at(100),(010),(001), and(406) is calculated to be 3.46, 2.60, 3.35, and 3.68 W=/(m·K),respectively. The laser output anisotropy of a continuous-wave(CW) and tunable laser is characterized, accordingly. A maximum output power of 6.09 W is achieved in the Yb,Nd∶Sc_(2)SiO_(5) crystal with(010) direction, corresponding to a slope efficiency of 48.56%. The tuning wavelength range in the Yb,Nd∶Sc_(2)SiO_(5) crystal orientated at(100),(010), and(001) is 68, 67,and 65 nm, separately. The effects of thermal properties on CW laser performance are discussed.

Yb∶YAG晶体的生长与激光性能

采用中频感应提拉法生长出了掺杂浓度的原子分数高达２０％的Ｙｂ∶ＹＡＧ晶体，探索了合适的晶体生长、退火工艺参数；研究了晶体中的杂质离子和色心；选用ＩｎＧａＡｓ半导体激光泵浦，通过激光腔的设计，研究了晶体的激光性能，获得了１０３０ｎｍ波长３００ｍＷ的脉冲激光输出，斜率效率为３０％。

掺Yb^(3+)激光晶体的研究进展

本文简要介绍了掺Yb3+ 激光晶体的发展历史 ;从Yb3+ 离子的能级结构出发 ,阐述了掺Yb3+激光材料的特点 ,介绍了几种掺Yb3+ 激光晶体的光谱特性 ,简述了近年来掺Yb3+ 激光晶体激光性能的研究进展 ;对掺Yb3+ 激光晶体未来的发展做了展望。

LD边抽运Yb∶YAG激光器性能的数值计算

以准三能级固体激光理论为基础,用数值方法研究了LD边抽运Yb∶YAG板条激光器的激光输出特性、温度效应、光学畸变和摩尔分数优化等性能。计算表明,Yb∶YAG可实现 100kW的激光输出,板条的尺寸在 130mm×60mm×3mm左右,Yb3+的摩尔分数小于 1%。从晶体的生长的角度看,生长出满足 130mm×60mm×3mm晶体元件加工需求的Yb∶YAG晶体是可行的。所以,Yb∶YAG是未来激光战术武器中的候选材料。

掺Yb^(3+)氧化镧钇透明激光陶瓷的光谱特性

采用传统陶瓷烧结工艺,在无压还原气氛下低温制备出透明性良好的掺Yb3+氧化镧钇透明激光陶瓷,测试了其在室温下的吸收光谱、发射光谱和荧光寿命.结果表明,掺Yb3+氧化镧钇透明激光陶瓷的吸收系数随着Yb3+掺杂浓度的增加而增大,最强吸收峰974 nm处的吸收截面为0.90~1.12×10-20cm2;主发射峰1 032 nm和1 075 nm处的发射截面分别为1.05×10-20cm2和0.87×10-20cm2;Yb3+掺杂浓度为5at.%时荧光寿命为1.38 ms,并随Yb3+掺杂浓度的增加而减小;当Yb3+掺杂浓度超过10at.%时,样品中存在严重的浓度猝灭.产生浓度猝灭的原因是高掺杂时离子间存在合作上转换和能量转移.

GdAl3(BO3)4及其Yb^3＋激活激光晶体的研究

采用顶部籽晶法从K2Mo3O10-B2O3助熔剂体系中生长出尺寸达到20mm的GdAl3(BO3)4(简称GAB)和Yb3+激活的晶体。测试了GAB晶体的〈100〉和〈001〉轴向热膨胀系数,确定了透光波长范围,计算了有效倍频系数和相位匹配角随波长的变化,结果表明GAB晶体在整个透光范围内均可实现相位匹配。测定了Yb3+:GAB晶体在室温下的偏振吸收和荧光光谱,进行了光谱计算,测试了晶体的激光性能,在1046nm处实现了2.1W激光输出,斜率效率达到58%。

掺Yb^(3+)石英光纤的制备及其激光性能

本文首次在国内报道了用ＭＣＶＤ 工艺研制出两种结构的掺Ｙｂ３ ＋ 石英光纤，包括简单梯度掺Ｙｂ３ ＋ 单模石英光纤和双包层结构掺Ｙｂ３ ＋ 石英光纤。在掺Ｙｂ３ ＋ 光纤激光实验中，实现了１ ０３０ｎｍ 的激光输出，输出功率达到４５ ｍ Ｗ 以上，斜率效率达到６８ ％ ；在掺Ｙｂ３ ＋ 光纤放大器中，１ ０５３ｎｍ 波长小信号增益达到了１５ ｄＢ。

Yb∶YAB晶体的生长及性质研究

本文首次报道了ＹｂｘＹ１－ｘＡｌ（ＢＯ３）４（简称Ｙｂ∶ＹＡＢ）晶体的生长及光学性质。根据测定的Ｙｂ∶ＹＡＢ晶体的折射率计算其一类位相匹配角θｍ（Ｉ）＝３４°１２′，与实验中测定的θｍ（Ｉ）＝３４°３８′符合的较好。在室温吸收谱９５６ｎｍ和９７５ｎｍ处存在两个吸收带，能与ＩｎＧａＡｓＬＤ有效耦合。１．０３μｍ和１．０４μｍ处各存在一荧光峰，１．０３μｍ处荧光寿命为１．３９７ｍｓ。

0.5at%Yb∶YAG晶体光谱与激光性能研究

采用提拉法生长Yb3+掺杂浓度为0.5at%高质量的Yb∶Y3Al5O12(Yb∶YAG)晶体。对晶体的结晶质量、分凝系数和光谱和激光性能进行了表征。结果表明:所生长的晶体结晶质量较好,在空气中退火后晶体吸收系数略有增加,晶体中自吸收效应的影响很小,具有宽的发射带。Yb∶YAG晶体和Yb∶YAG/YAG复合晶体分别在抽运功率为7.1 W和6.15 W的LD抽运下,获得2.19 W和1.354 W的连续激光输出,斜率效率分别为34.58%和25.9%。