共查询到20条相似文献,搜索用时 15 毫秒
1.
Auge F. Druon F. Balembois F. Georges P. Brun A. Mougel F. Aka G. Vivien D. 《Quantum Electronics, IEEE Journal of》2000,36(5):598-606
We present a theoretical and experimental analysis of a diode-pumped Yb3+-doped Ca4GdO(BO3)3 (Yb:GdCOB) laser. A new model for a diode-pumped quasi-three-level laser is described. The effects of absorption saturation, temperature profile, and the beam quality M2 factor of the pump diode have been taken into account, for the first time to our knowledge. We have obtained a good agreement between experimental measurements and theoretical calculations with two different pump wavelengths, 902 and 976 nm. Our model has given good predictions of the laser performances for different crystal temperatures and different M2 factors of the pump beam. As much as 440 mW of output power (at 1082 nm) have been achieved for 640 mW of absorbed pump power at 976 nm, corresponding to one of the highest slope efficiencies (81%) ever obtained with Yb-doped lasers 相似文献
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采用高温固相还原反应合成了新型单相荧光粉Ca 9NaZn(PO4)7(CNZP):Ce3+,Tb3+,并对样品的发光性能和 能量传递过程进行分析。研究表明,在波长为310nm紫外光激发下, Ce3+、Tb3+ 双掺体系发射光谱同时包含Ce3+的宽带和Tb3+的 线状发射光谱;在CNZP体系中,Ce3+→Tb3+间能量传递的临界距离Rc=1.216nm,为共振能量传递,机理被证实为四 极子-四极子相互作用。从CIE色度坐标图可以看出,利用 能量传递效果和改变CNZP:0.02Ce3+,yTb3+中 掺杂离子的相对浓度可实现颜色从蓝紫色到绿色的调控,表明所得荧光粉在WLED用紫 外激发荧光粉中具有潜在的应用价值。 相似文献
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采用高温固相法合成了一系列Gd2(MoO4)3:D y3+, Tm3+白色荧光粉。通过XRD衍射、荧光光谱分析对荧光粉的物相结构以及发光性能进 行了研究,且通过色坐标监测样品的发 光颜色。发射光谱显示荧光粉Gd2-x(MoO4)3:xDy 3+在387nm激发下,Dy3+的2F9→6H15/2跃 迁的蓝光发射及2F9→6H13/2跃迁的黄光发射最强,随着Dy3+浓度增加 ,色坐标由白光向黄 光转移。在Gd2(MoO4)3:Dy3+,Tm3+的发射光谱中,在361nm激发下,可以同时看到Dy3+的 黄光发射和Tm3+的蓝光发射,即Dy3+的2F9/2→6H13/2黄光 跃迁和Tm3+的1D2→3F4蓝光跃 迁,因此,通过调节Dy3+,Tm3+的浓度可以使样品发出白光。当Dy3+浓 度为12%,Tm3+ 浓度为7~14%时,样品皆在白光区。当Dy3+,Tm3+浓度均为12%时,样品的色 坐标为(0.338,0.329 )最接近标准白光(0.33)。同时,在 Dy3+与Tm3+共掺的体系中,可以看到Tm3+向Dy3+的能量传递。 相似文献
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Junhai Liu Mateos X. Huaijin Zhang Jing Li Jiyang Wang Petrov V. 《Quantum Electronics, IEEE Journal of》2007,43(5):385-390
High-power continuous-wave laser operation near 1 mum was demonstrated at room temperature with c-cut and a-cut Yb:YAl3(BO3)4 crystals end-pumped by a fiber-coupled diode laser. Using a 2-mm-thick c-cut crystal, 10.6 W of output power was generated with an optical-to-optical efficiency of 65% and a slope efficiency of 72%. The complex polarization state of the generated laser radiation was also studied. With a 2-mm-thick a-cut crystal, sigma-polarized laser oscillation was obtained, producing a maximum output power of 8.1 W; the optical-to-optical and slope efficiencies were 56% and 61%, respectively. Complete absorption and emission cross section spectra of the Yb:YAl3(BO3) 4 crystal were also derived, revealing very strong anisotropy of the spectroscopic properties 相似文献
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采用固相法于550℃灼烧4h,合成了Eu3+ 单掺杂的NaY(MoO4)2材料,研究了材料的 发光特性。X射线衍射(XRD)结果显示,掺杂少量杂质的材料仍为纯相的NaY(MoO4)2。以 393nm波长 近紫外光作为激发源时,NaY(MoO4)2:Eu3+可以发射主峰位于616nm波长的红色光,对应Eu3+的 5D0-7F2跃迁发射。研究发现,增大Eu3+掺杂量 时,对应材料的发射强度会逐渐增大,但是 未发现浓度猝灭现象,通过相应的衰减曲线解释了此结果。测量不同Eu3+掺杂量下 , NaY(MoO4)2:Eu3+的色坐标结果显示,色坐标基本不变,位于红色区域。上述 结果表明, NaY(MoO4)2:Eu3+在白光LEDs领域有一定的应用潜力。 相似文献
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采用高温固相法制备了Sr5-x (PO4)2SiO4:xEu2+(x =0.010,0.015,0.020,0.025,0.050, 0.100)荧光粉,研究掺杂 浓度和测试温度对荧光粉发光性能的影响。随着Eu2+掺杂浓度的增加,发射强度呈现 先增大后减小的变化 趋势,并在x=0.015时达到最大值。Eu 2+掺杂浓度较低时(x≤0.025),Eu2+取代不同格位的 Sr2+,使得发射 光谱具有双发射峰;当x>0.025时,由于 存在Eu 1到Eu 2的能量传递使发射光谱中Eu 1的峰位消失,只存 在Eu 2的峰位。发射光谱随Eu2+浓度增大出现了红移现象,这是由于半径较小的Eu 2+(0.109nm)取代较 大的Sr2+(0.113nm)使得晶胞收缩,晶场强度增大,从而导 致Eu2+的5d能级劈裂程度增大,电子跃迁释 放能量降低。此外,测试温度增加时,发射光谱出现与Varshini方程不相符的蓝移现象,这 是晶格结构稳定性和声子辅助隧穿效应共同作用使较小波长的Eu 1的发射居于主导地位的结 果。 相似文献
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用干涉法测量了低对称晶体GdCa4O(BO3)3的全部电光系数。为了分离测量交叉电光系数γ51,γ53,γ42和γ62,采用了新的样品趋向。测量结果为:γ11=0.4pm/V,γ21=0.5pm/V,γ31=0.6pm/V,γ13=0.1pm/V,γ23=0.4pm/V,γ33=2.0pm/V,γ51=0.7pm/V,γ42=0.5pm/V,γ62=0.8pm/V。 相似文献
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Yujin Chen Yanfu Lin Xinghong Gong Zundu Luo Yidong Huang 《Quantum Electronics, IEEE Journal of》2007,43(10):950-956
An Er:Yb:GdAl3(BO3)4 crystal was grown and room-temperature polarized absorption, emission, and gain spectra were investigated. Fluorescence decay curves of Er3+ at 1530 nm and Yb3+ at 1040 nm in the crystal were measured. Efficient laser operation of Er:Yb:GdAl3(BO3)4 crystal at 1.5-1.6 mum was realized. Quasi-continuous-wave output powers of 1.8 W with slope efficiency of 19% and 0.78 W with slope efficiency of 14% were achieved in diode-pumped c-cut and c-cut and a-cut crystals, respectively. The output spectrum and polarization of Er:Yb:GdAl3(BO3)4 laser were also investigated. 相似文献
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Won Kweon Aang Qing Ye Hammons D. Eichenholz J. Jinhong Lim Richardson M. Chai B.H.T. van Stryland E.W. 《Quantum Electronics, IEEE Journal of》1999,35(12):1826-1833
We describe experiments characterizing a new nonlinear optical crystal, YCa4O(BO3)3 (YCOB). This crystal has a number of advantages over other commonly available nonlinear optical crystals. It has a higher nonlinear coefficient than KDP, can be fabricated to large sizes (~3-in diameter, 8-in length), and has a high damage threshold. Moreover, this new nonlinear optical crystal is nonhygroscopic, has good optical quality and mechanical properties, allowing easy optical polishing. This crystal, YCa4 O(BO3)3, commonly termed YCOB, is one of a family of new nonlinear crystals, the oxyborates, that include RECa4O(BO3)3 (RE=La3+, La 3+, Y3+, Sm3+, Gd3+, Er3+, and Nd3+). In this paper, we also successfully demonstrate a technique for improving the nonlinear optical properties of this crystal. This technique, ion substitution, has previously had limited success with other crystal hosts. However, the inclusion of yttrium in YCOB provides the opportunity to exploit this technique. Yb3+, which has larger mass, but approximately the same atomic size as Y3+ can be substituted into the crystal structure without introducing stress and nonuniformities. A systematic investigation of the linear and nonlinear characteristics of several crystals doped with various levels of Yb demonstrate that selective substitution of Yb in YCa4O(BO3)3 improves the second-harmonic conversion efficiency by increasing the optical nonlinearity 相似文献
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采用水热法结合高温退火处理制备了YPO4:Ln3+(Ln=Eu,T b)荧光粉。通过X射线 粉末衍射(XRD)、扫描电镜(SEM)和荧光光谱(PL)对样品的结构、形貌和发光性能进行 表征。结果 表明:在水热条件下合成了含结晶水六角相结构的YPO4·0.8H2O :Eu3+和YPO4·0.8H2O:Tb3+前躯体;经过 800 ℃高温烧结2h后,前躯体 失去结晶水后得到球形、尺寸均一、表面光滑、四方锆石结构的YPO4:Eu3+和 YPO4:Tb3+荧光粉,颗粒平均粒径约为200 nm。在396 nm波长激发下,YPO4:Eu3+荧光粉可以获得Eu3+离 子的跃迁能级5D0→7FJ(J=1-4)特征发射,以磁偶极跃迁5D0→7F1(596 nm)的发光强度最强,观察到橙 红色发射,且Eu3+的最佳掺杂摩尔分数为11%。同时,YPO4: Tb3+荧光粉在372 nm的光激发下,在548 nm 处的5D4→7F5跃迁具有最高的荧光强度,观察到绿光发 射,且Tb3+最佳掺杂摩尔分数为7%。 相似文献
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Na_5Sm(WO_4)_4发光晶体的生长及光谱特性 总被引:2,自引:1,他引:2
本文报道了用助熔剂缓冷法生长新型发光晶体Na_6Sm(WO_4)_4,计算了它的晶格常数,测定了它的红外光谱、吸收光谱、荧光光谱和激发光谱,并确定了晶体中Sm~(3+)离子的能级.研究表明,该晶体是有前途的激光晶体. 相似文献
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测定了室温下Na5TbxEu1-x(MoO4)4的发射光谱。发现随x的增加,Tb^3+离子546nm(^5D4→^7F5)的荧光发射亦随这增加。同时观察到,当x>0.7时,发光相对强度变化会出现突变。 相似文献
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《Quantum Electronics, IEEE Journal of》2007,43(2):157-167
The continuous-wave laser operation of Nd-doped tetragonal NaLa(WO 4)2 crystal is studied at room temperature by optical pumping in the spectral region overlapping AlGaAs diode laser emission. This crystal has inhomogeneously broadened optical bands. From the room-temperature spectroscopic parameters determined it is found that the optimum Nd concentration for the 4F3/2rarr4IJ laser channels must be in the 3-5 at.% range. For J=11/2 and 13/2 channels (lambdaap1.06 and 1.3 mum) the most favourable polarization configuration is parallel to the crystallographic c axis, while for J=9/2 little polarization dependence of the laser efficiency is predicted. Laser operation was achieved with a 3.35 at.% Nd-doped sample grown by the Czochralski method. The laser operation was tested in an hemispherical optical cavity pumped by a Ti:sapphire laser. Stimulated emission at lambda=1056 nm was achieved for a wide spectral pumping range, lambda=790-820 nm. Stimulated Raman scattering was achieved in the picosecond regime with an efficiency similar to that of monoclinic KY(WO4)2 reference compound 相似文献
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Marshall C.D. Smith L.K. Beach R.J. Emanuel M.A. Schaffers K.I. Skidmore J. Payne S.A. Chai B.H.T. 《Quantum Electronics, IEEE Journal of》1996,32(4):650-656
The performance of the first diode-pumped Yb3+-doped Sr 5(PO4)3F (Yb:S-FAP) solid-state laser is discussed. An InGaAs diode array has been fabricated that has suitable specifications for pumping a 3×3×30 mm Yb:S-FAP rod. The saturation fluence for diode pumping was deduced to be 5.5 J/cm 2 for the particular 2.8 kW peak power diode array utilized in our studies. This is 2.5× higher than the intrinsic 2.2 J/cm 2 saturation fluence as is attributed to the 6.5 nm bandwidth of our diode pump array. The small signal gain is consistent with the previously measured emission cross section of 6.0×10-20 cm2, obtained from a narrowband-laser pumped gain experiment. Up to 1.7 J/cm3 of stored energy density was achieved in a 6×6×44 mm Yb:S-FAP amplifier rod. In a free running configuration, diode-pumped slope efficiencies up to 43% (laser output energy/absorbed pump energy) were observed with output energies up to ~0.5 J per 1 ms pulse. When the rod was mounted in a copper block for cooling, 13 W of average power was produced with power supply limited operation at 70 Hz with 500 μs pulses 相似文献
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采用激光烧结技术快速成功地将比例适当的Al2O3和WO3粉末合成了形貌良好且致密的Al2(WO4)3材料,并对该材料采用多种分析手段进行了分析。 拉曼光谱分析说明在合适工艺参数下激光烧结可避免原料挥发,使原料完全参与反应。X射线衍射(XRD)分析表明合成物主要是Al2(WO4)3,属空间群Pnca,具有正交结构,可能显示负热膨胀特性,另外还含有少量的AlxWO3(x≤1)和WO3-x(x<1)。扫描电镜(SEM)发现合成物晶粒呈球形、细小、排列致密、少有气孔、尺寸约在10 nm左右。能量散射光谱(EDS)分析显示合成物内部成分分布均匀。热分析则得出合成物中少许杂相为复杂非平衡相。 相似文献
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用助熔剂法从KF-KCl熔体中生长出了K_3Nd(PO_4)_2和K_3Nd_xLa_(1_x)(PO_4)_2晶体。化学组成分析和X射线衍射分析证明,所得到的晶体是K_3Nd(PO_4)_2。测定了它们的红外光谱、吸收光谱、荧光光谱和荧光寿命。 相似文献
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本文利用X射线光电子能谱(XPS),飞行时间二次离子质谱(TOF-SIMS)和电流-电压特性(I-V)对不同硫化铵溶液((NH4)2S)钝化后的锑化镓(GaSb)表面化学性质进行了研究。通过对比,发现中性(NH4)2S S溶液对GaSb表面的钝化能力要优于纯(NH4)2S溶液和碱性(NH4)2S S溶液。碱性(NH4)2S S溶液在有效去除GaSb表面氧化物的同时形成硫化物产物以改善器件性能。TOF-SIMS测试结果从另一方面证实纯(NH4)2S溶液钝化也会形成硫化物产物,但该产物在纯(NH4)2S溶液中是可溶的,以至于很难稳定地存在。3D光学轮廓仪测试结果显示中性(NH4)2S S溶液钝化的GaSb表面具有最低的粗糙度。I-V测试结果表明中性(NH4)2S S溶液钝化能显著提高GaSb基肖特基二极管的电学性能。综上所述,中性(NH4)2S S溶液的钝化效果在改进GaSb表面性质方面具有最优的结果。 相似文献