镱掺杂石榴石基平面波导激光陶瓷的制备与性能研究

发布时间：2018-01-05 08:33

本文关键词：镱掺杂石榴石基平面波导激光陶瓷的制备与性能研究　出处：《江苏大学》2017年硕士论文　论文类型：学位论文

【摘要】：面向高功率、高效率、高光束质量的全固态激光器的不断发展,激光增益介质热效应是限制其发展的主要因素,因此有必要对激光材料的组成分布进行优化设计。平面波导结构利用其独特的结构设计能够有效地减小热效应,还能实现低阈值、高功率激光输出。相比于单晶,激光陶瓷的结构可设计性强,易实现多种应用。通过流延成型方法结合真空烧结技术,就可以在陶瓷制备过程中得到平面波导结构。在众多稀土离子掺杂的石榴石基质的激光陶瓷中,Yb:YAG透明陶瓷具有单位面积增益高;吸收带宽,无需严格的温度控制即可获得合适的泵浦源波长,实现高浓度掺杂且没有浓度猝灭效应等优异的性能,而且目前激光二极管(LD)的泵浦功率不断提高也解决了早期Yb:YAG泵浦阈值高,不易泵浦的缺点。平面波导Yb:YAG透明陶瓷成为了高功率、高效率固体激光器的理想增益介质。然而,随着Yb离子在YAG中掺杂浓度的增加,Yb:YAG的热导率会骤然下降,当基质为LuAG时,随Yb3+离子掺杂浓度的增加,Yb:LuAG热导率下降缓慢,且当Yb离子掺杂浓度超过5at.%时,Yb:LuAG的热导率比Yb:YAG的高。Yb:LuAG还具有较大的有效发射截面,更利于超短脉冲激光的输出。平面波导Yb:LuAG透明陶瓷有望成为高功率超短脉冲激光器的理想增益介质。本论文选取Yb掺杂的石榴石基平面波导透明陶瓷为研究对象,以商业氧化物粉体为原料,采用非水基流延成型结合真空烧结技术制备了平面波导激光陶瓷,并对陶瓷的显微结构、光学性能及离子扩散分布展开研究。首先,采用非水基流延成型制备了平面波导YAG/10at%Yb:YAG/YAG陶瓷素坯,其中对原料粉体、流延膜、不同阶段的素坯进行了微观形貌观察。经过1775oC烧结30h得到的样品在可见光波段透过率接近80%,晶界干净清晰但存在少数晶内气孔。基于扩散定律研究了波导层内Y和Yb离子扩散分布,并分别拟合计算了扩散系数。经过工艺的调整优化及烧结温度的改变,在1760oC烧结30h得到了平面波导YAG/10at%Yb:YAG/YAG透明陶瓷。3.5mm厚的样品透过率接近理论值,晶界清晰干净,无气孔及第二相。通过ICP-MS测试得到激活离子Yb的单向扩散距离为215μm。尺寸3.5×3.5×3.5mm3的样品实现了连续激光输出,其中在三镜腔下获得最佳激光性能显示单模激光,最大输出功率为1.6W,斜率效率为34.4%。此外,采用流延成型和陶瓷烧结工艺制备了平面波导LuAG/10at%Yb:LuAG/LuAG透明陶瓷,分别在1775、1800、1825oC下进行预烧结后进行热等静压(HIP)1700oC烧结后处理,重点研究了HIP后处理的陶瓷微观形貌、光学性能及掺杂离子Yb的扩散分布。随着预烧温度的升高,HIP后处理样品晶粒尺寸逐渐变大,透过率逐渐提高。其中预烧结温度为1825oC时,2mm厚样品透过率在1100nm处达74%,且Yb3+分布区域最宽,单向扩散距离达170μm。
[Abstract]:For high power, high efficiency, continuous development of all solid state laser with high beam quality, the laser gain medium thermal effect are the main factors that restrict its development, so it is necessary to optimize the composition distribution of laser materials. Planar waveguide structure with its unique structural design can effectively reduce the thermal effect, but also to achieve low threshold high power laser output. Compared to the single crystal structure of laser ceramics can be designed, easy to implement many applications. By casting method combined with vacuum sintering technology, you can get a planar waveguide in the ceramic preparation process. In many garnet laser ceramic matrix doped with rare earth ions in transparent Yb:YAG ceramics with unit area high gain; absorption bandwidth, gain pumping source with suitable wavelength without strict temperature control can achieve high doping concentration and no concentration quenching effect. The same performance, and the current of laser diode (LD) pump power increasing but also solve the early Yb:YAG pumping threshold is high, not easy to pump faults. Planar waveguide Yb:YAG transparent ceramics become a high power, high efficiency laser gain medium ideal. However, with the increase of Yb doping concentration in YAG, Yb:YAG the thermal conductivity will suddenly drop, when the matrix is LuAG, with the increase of Yb3+ doping concentration, the thermal conductivity of Yb:LuAG decreased slowly, and when the doping concentration of Yb exceeds 5at.%, the thermal conductivity of Yb:LuAG is also greater than the high effective emission cross section of.Yb:LuAG Yb:YAG, more conducive to the ultrashort pulse laser output planar waveguide Yb:LuAG. Transparent ceramics is expected to become the ideal gain medium high power ultrashort pulse laser. Garnet based planar waveguide transparent ceramics doped Yb this paper selected as the research object, taking the oxide powder industry As material, using planar waveguide laser ceramics was synthesized by vacuum sintering technique for non aqueous tape casting of ceramic, and the microstructure, optical properties and ion diffusion distribution is researched. Firstly, the planar waveguide YAG/10at%Yb:YAG/YAG ceramic blank was fabricated by non aqueous tape casting system, the raw material powder, cast film, different the blank of morphology observation. After 1775oC sintered 30h samples obtained in visible light transmittance is close to 80%, but there is a clear boundary. The crystal pores in the waveguide layer Y and Yb ion diffusion diffusion distribution based on the law, and fitting the diffusion coefficients are calculated. After the adjustment and optimization of sintering the temperature change process, the samples of transparent ceramics.3.5mm thick planar waveguide YAG/10at%Yb:YAG/YAG transmittance is close to the theoretical value obtained in the sintering of 1760oC 30h, the clear boundary clean, no Stomata and the second phase. Measured by ICP-MS unidirectional diffusion distance activated ion is 215 M. Yb size 3.5 x 3.5 x 3.5mm3 samples to realize continuous laser output, which won the best performance in the three mirror cavity laser display single-mode laser, the maximum output power of 1.6W, the slope efficiency of 34.4%. in planar waveguide LuAG/10at%Yb:LuAG/LuAG transparent ceramics prepared by tape casting and sintering process, pre sintering under 177518001825oC respectively after hot isostatic pressing sintering (HIP) 1700oC postprocessing, ceramic micro morphology focuses on the HIP postprocessing, distribution and optical properties of Yb doped ions. With increasing calcination temperature and HIP postprocessing samples the grain size becomes larger, the transmittance gradually increased. The pre sintering temperature is 1825oC, 2mm thick sample transmittance at 1100nm was 74%, and the distribution area of Yb3+ is the widest, one-way extension The dispersion distance is 170 mu m.

【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ174.1

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