LD泵浦Nd:YVO4倍频调Q激光器的输出特性

根据四能级非线性速率方程,对连续LD泵浦Nd:YVO4/Cr4+:YAG/KTP腔内倍频被动调Q绿光激光器的输出特性进行了数值模拟.理论分析与实验相一致,所得结果对该类器件参数优化具有参考价值.     

Planar optical waveguides prepared in GIL49 and BK7 glass substrates by K+-Na+ ion exchange with the electric field assistance

This report focuses on research into waveguides prepared by K⁺-Na⁺ ion exchange with the help of an electric field, and the subsequent comparison with waveguides prepared by pure thermal ion exchange. The goals of this work were to determine the characteristics of and to address the technological problems associated with waveguides prepared in two types of highly pure optical glass: special soda-lime silica GIL49 glass produced from pure raw materials and commercially prepared borosilicate BK7 glass. An appropriate chemical mixture, KNO₃:Ca(NO₃)₂ in the molar ratio of 41:59, was used as the source of potassium ions. Experiments were conducted at temperatures between 250 and 410°C, and electric field values between 0 and 150 V/mm. The number of modes, depth, profile, and the change in refractive index (Δn) were measured for samples from each type of glass under various technological conditions. All of these parameters can be controlled accurately and repeatedly by the electric field. These experiments have also shown that a particular advantage of these types of pure glass is the low waveguide optical losses (0.1 to 0.2 dB/cm) attainable.     

Nd^3＋,YAG激光和CO2激光对豚鼠中耳和耳蜗的显微及超微结构的影响

为了研究ＹＡＧ激光ＣＯ２激光行鼓膜造孔对听力的影响，我们用不同功率密度的激光照射豚鼠鼓膜不同时间后观察中耳和耳蜗显微和超微结构的变化。结果发现光关节末端输出功率１．５８Ｗ／ｍｍ＾２的ＣＯ２激光照射豚鼠鼓膜２秒，相同功率密度的ＹＡＧ激光照射１０秒可引起鼓膜穿孔，听骨链和耳蜗凝固或点状炭化；显微镜观察见凝固和炭化处柯蒂氏器官均明显破坏或变形，其内部分有炭化灶和／或炭化颗粒。激光输出功率密度愈大，损伤听     

定向棱镜改善Cr4+:YAG调Q输出稳定性的研究

为了改善Cr4+:YAG被动调Q激光器的输出稳定性,采用了定向棱镜谐振腔,通过实验得到了以下结果:单脉冲能量稳定度由7.3%提高到2.2%,脉宽稳定度由13.5%提高到6.5%,频率精度由0.01%提高到0.005%,输出脉冲波形稳定光滑。研究表明,采用定向棱镜谐振腔技术的Cr4+:YAG被动调Q激光器的输出稳定性较原平平腔激光器得到了显著改善。另外还报道了定向棱镜谐振腔技术消除Cr4+:YAG被动调Q激光器子脉冲的现象。     

水解工艺Yb3＋/Al3＋共掺石英玻璃的研制及特性表征

利用四氯化硅(SiCl₄)水解掺杂法结合高 频等离子体粉末熔融技术制备了Yb3＋/Al3＋共掺石英玻璃,并利用 X射 线衍射(XRD)、傅里叶变换红外(FTIR)光谱分析和热膨胀分析等对所制备玻璃样品的结 构特性、物理特性和光谱特 性进行了表征。结果表明,制备的Yb3＋/Al3＋共掺石英玻璃的密度和折 射率值与纯石英玻璃相接近,并且呈现出 较好的玻璃态,其热膨胀系数为2.87×10－6,具有较好的Yb3＋和Al 3＋掺杂均匀性,以及Yb3＋典型的吸 收特性和发射特性,表明采用本文方法制备的Yb3＋/Al3＋共掺石英玻璃 已具备成为大功率激光材料的潜质。     

溶液燃烧法制备纳米LaAlO3:Dy3+及发光性能研究

通过溶液燃烧法以La(NO3)3·6H2O,Dy(NO3)3·9H2O和Al(NO3)3·9H2O及C2H5NO2为原材料制备纳米粉体Lal-xDyxA1O3(x=0,0.01,0.02,0.03,0.04,0.05).采用X射线衍射、扫描电子显微镜、紫外-可见漫反射光谱和荧光光谱研究晶体结构、形貌、发光强度等内容,结果表明,通过溶液燃烧法在800℃下煅烧4h,Dy3+离子进入到LaAlO3晶格中,荧光光谱分析结果表明Lal-xDyxAlO3粉体在370 nm的激发波长下,发光主峰位于423 nm处,在掺杂比例为0.03时发光强度最高,其禁带宽度5.54 eV与理论值5.6 eV相近.     

CaHPO4:Tb3+纳米晶的相演变与发光性能研究

以无水乙醇作反应溶液,采用室温共沉淀,合成 了CaHPO₄:Tb³⁺绿色荧光粉。用X射线衍射(XRD)、 扫描电镜(SEM)、荧光(PL)光谱、热重(TG)和差示扫描量热(DSC)等分别对所得样品的相结构、形貌、发光 性能以及热稳定性进行研究。研究结果表明,在室温条件下,得到了纯三斜相CaHPO₄:Tb ³⁺;当烧结温度为 400℃时,开始出现相结构转变;温度升高到500℃以上时,晶相完全转变为纯四方晶系Ca₂P₂O₇,但样 品的形貌变化很小,都为分散性比较好、尺寸分布比较均匀的纳米颗粒。同时,利用激发光 谱和发射光谱 研究了Tb³⁺在CaHPO₄和Ca₂P₂O₇基质中的发光性能,在波长为370nm紫外光的激发下,都观察到Tb³⁺的特 征跃迁(⁵D₄→⁷FJ,J=3~6),其中以⁵D₄→⁷F₅ 跃迁发射(544nm)为主,而且CaHPO₄:Tb³⁺的发光强度要明 显强于Ca₂P₂O₇:Tb³⁺。     

ZASP玻璃荧光体的激发波长依赖性及Dy3＋掺杂的荧光色彩调谐

采用熔融法制备了锌铝锑磷酸盐(ZASP)玻璃荧光 体,研究了其荧光色彩对激发波长的依赖性和Dy³⁺掺杂的色彩调谐作用。短波紫外(U VC)和中波紫外(UVB)激发下,ZASP基质玻璃 呈现Sb³⁺的宽谱带发射,色彩位于蓝白光和蓝光区域。差异性光谱行为表明,玻璃中 存在异质 性的Sb³⁺发光中心,导致玻璃荧光对激发波长产生依赖行为。Dy³⁺引入ZASP玻 璃后,产生归属 于Dy³⁺的约484nm波长窄带发 射,其在UVC和UVB激发下的发光有效性相当程度上归因于Sb ³⁺到Dy³⁺的能量传递。Dy³⁺的暖色成分使ZASP玻璃荧光总体上从蓝白区 向白光区移动,同时 也对荧光的激发波长依赖趋势产生显著影响,丰富了荧光发射色彩的多样性,为高质量荧光 器件的研发提供了可能。     

Comparison of p–n junction formed by BF2 and B implantation in silicon microstrip detector with low and high thermal budget: impact of fluorine on electrical characteristics

The influence of crystal damage on the electrical properties and the doping profile of the implanted p⁺–n junction has been studied at different annealing temperatures using process simulator TMA-SUPREM4. This was done by carrying out two different implantations; one with implantation dose of 10¹⁵ BF₂⁺ ions/cm² at an energy of 80 keV and other with 10¹⁵ B⁺ ions/cm² at 17.93 keV. Substrate orientation 1 1 1 of phosphorus-doped n-type Si wafers of resistivity 4 kΩ cm and tilt 7° was used, and isochronally annealing was performed in N₂ ambient for 180 min in temperature range between 400°C and 1350°C. The diode properties were analysed in terms of junction depth, sheet resistance. It has been found that for low thermal budget annealing, boron diffusion depth is insensitive to the variation in annealing temperature for BF₂⁺-implanted devices, whereas, boron diffusion depth increases continuously for B⁺-implanted devices. In BF₂⁺-implanted devices, fluorine diffusion improves the breakdown voltage of the silicon microstrip detector for annealing temperature upto 900°C.For high thermal budget annealing, it has been shown that the electrical characteristics of BF₂⁺-implanted devices is similar to that obtained in B⁺-implanted devices.