腔内OPO2μm脉冲激光器

设计了基于KTP晶体的内腔式光参量振荡(OPO)2μm脉冲激光器。理论计算了KTP-OPO波长调谐特性及相位匹配参数,采用电光调QNd:YAG1.064μm激光泵浦的KTP晶体,在XZ主平面内,实现了Ⅱ类相位匹配,选用Φ4mm光阑限制光束,分别对单块KTP和为补偿走离效应采用两块向对放置的KTP晶体进行了实验,获得了最高25mJ的脉冲2.12μm激光输出,电光转化效率1.14‰。     

Ce~(4+)∶KTP晶体倍频效应的研究

采用等离子体发射光谱法测定了在掺入Ce4 +不同浓度条件下所生长的Ce4 +∶KTP晶体中的Ce4 +含量 ,并计算出Ce4 +在相应晶体生长体系中的分配系数 ;采用激光粉末倍频法对晶体进行了倍频效应测试 ,并将所得数据与纯KTP晶体做了比较 ,发现在给定的掺质浓度范围内 ,晶体的倍频效应均有所增强 ,且倍频效应随晶体中掺质含量的增大而先增强 ,后减弱 ,文中对这种现象进行了讨论。     

4～5μm全固化可调谐激光实验研究

报道了采用KTP晶体和LiIO3晶体实现4~5μm可调谐激光输出的光参量振荡器(OPO)至差频产生器(DFG)的全固化结构和相应的实验结果。其中光参量振荡器的抽运源为倍频Nd∶YAG激光,差频产生器的抽运源分别是上述光参量振荡器激光和Nd∶YAG基频激光经KTP倍频晶体后剩余的1.064μm激光。实验中Nd∶YAG基频脉冲激光脉宽12 ns,单脉冲能量300 mJ。观察到最大倍频效率达到66.7%,KTP参量量子转换效率达到50%,差频量子转换效率为1.5%,在4.45μm得到了单脉冲100μJ的激光输出。差频光的调谐范围为4.1~4.5μm,发散角为垂直方向12 mrad,水平方向4 mrad。     

非临界相位匹配的人眼安全KTP光参量振荡器

报道了一台电光调Q,Nd∶YAG激光器泵浦的KTP脉冲光参量振荡器(OPO),获得了高单脉冲能量的人眼安全激光输出。KTP晶体按非临界相位匹配θ=90°和φ=0°进行切割,在Ⅱ类相位匹配(o→o+e)下,1.064μm的泵浦激光转换为人眼安全的1.57μm激光。KTP晶体的尺寸为10 mm×10 mm×20 mm,OPO谐振腔采用信号光单谐振的外腔结构,当二极管泵浦的Nd∶YAG激光器输出的1.064μm激光单脉冲能量为350 mJ,重复频率为10 Hz时,获得了单脉冲能量117 mJ的1.57μm激光输出,转换效率约为33.4%。     

23.6W高效率2 μm激光器

报道了一台高重复频率高效率2μm激光器.理论计算了1.064μm激光抽运Ⅱ类相位匹配KTP晶体的角度调谐曲线,得出KTP晶体按φ=0°,θ=54°切割可获得近简并波长的2μm激光输出.使用1.064μm Nd∶YAG模块作为抽运源,抽运内腔式双晶体走离补偿双谐振光参量振荡器(DROPO),在7 kHz声光调Q频率下,获得23.6 W的2.12μm激光输出,808 nm激光二极管(LD)出光获得2μm激光的斜率效率超过19%.     

KTP——一种新型的Nd:YAG激光倍频晶体

一、KTP晶体KTP(KTiOPO_4)是Nd:YAG激光(1.06μm)倍频的理想材料。KTP属于K_xRb(1-x)TiOPO_4族,斜方结构(点群mm2 )的双轴晶体。晶体常数:a=12800(?),b=6400(?),C=10580(?)。表1列出了KD~*P,LiNbO_3及KTP晶体特性的最重要数据。令人注意的首先是与KDP族(KD~*P或KDP)相比,KTP的透过范围大,非线性系数大,因此可用于有效倍频。表1 KD~*P、LiNbO_3及KTP晶体的特性     

人眼安全1.57μm OPO激光测距机

研制成功人眼安全1.57μmOPO激光测距机,并进行了室外测距实验,在能见度V约10km时测到7050m远处的烟囱,测距精度±5m,重复频率达20pps.该测距机采用紧凑小型的水冷灯泵电光调Q(Ce,Nd):YAG激光器泵浦磷酸钛氧钾(KTP)1.57μm单谐振OPO器件,输出12mJ,脉宽～6ns.接收元件选用铟镓砷(InGaAs)PIN探测器.     

KTA和KTP晶体参量激光特性研究

讨论了激光二极管阵列(LDA)侧面泵浦声光调Q Nd:YAG内腔式光学参量振荡器(OPO)的阈值特性;在相同的实验条件下,对比分析了KTA和KTP晶体参量激光输出特性.当声光重复频率为4kHz,输出镜透过率为30%,泵浦电流为14.5A时,波长为1.57μm,KTA晶体参量激光平均输出功率最大为613.4mW,脉冲宽度约2.5ns,峰值功率超过61kW.     

基于楔形Nd:YVO_4/KTP双折射滤波的单频绿光激光器

通过研究双折射晶体Nd:YVO_4的偏振特性,利用楔角为10°的Nd:YVO_4激光晶体和倍频晶体KTP(磷酸钛氧钾)在绿光激光器中构造了一个新型双折射滤波器。理论分析了KTP晶体的长度、基频光在KTP中的入射角度和KTP的温度对双折射滤波器选频的影响。实验中使用长度为4.4,5,7 mm的KTP,采用V型腔结构,最后分别获得了90,120,104 mW的单频绿光。实验结果表明,由楔形Nd:YVO_4和KTP构成的双折射滤波器成功实现了激光单纵模运转,且方法简单易行。当KTP晶体长度为5 mm时,测得楔形Nd:YVO_4/KTP激光器的单纵模运转温度范围约为5℃。     

Ar+激光器泵浦的连续光学参量振荡器的理论设计

对Ar 激光器产生的514.5nm的连续光泵浦KTP晶体的光学参量振荡器(CW - KTP -OPO)做了理论分析,讨论了KTP晶体采用Ⅱ类临界相位匹配(CPM)时的角度调谐曲线、有效非线性系数以及走离角,并针对所设计的条件计算了KTP晶体的泵浦阚值.合理设计腔内各个器件的参数,最终确定晶体切割角度为θ=67°,ψ=0°,此时可以产生中心波长为1.55μm的信号光.     

Study of the nonlinear optical properties of 7.5 mol% Nb:KTPcrystals

Sellmeier's equations and the equations for the thermal principal refractive index coefficients as a function of wavelength fur 7.5 mol% Nb:KTP crystals are presented. Based on these equations, the nonlinear optical parameters for 7.5 mol% Nb:KTP crystals, especially the angular, spectral, and temperature acceptance bandwidths, are calculated. By comparing these results with KTP and KNbO₃ crystals, 7.5 mol% Nb:KTP crystals show better performance than KNbO₃ crystals in generating blue coherent light by direct second-harmonic generation of a semiconductor diode laser     

Second harmonic generation phase-matching locus for 7.5 mol% Nb:KTPcrystals at near-infrared wavelengths

Both the type-II second harmonic generation (SHG) phase-matching locus in the three principal planes of 7.5 mol% Nb:KTiOPO₄ (KTP) crystals for wavelengths less than 1.8 μm and the type-II SHG phase-matching locus for 7.5 mol% Nb:KTP crystals for wavelengths of 970, 980, 1064.2, and 1311.4 nm are calculated on the basis of the Sellmeier equations. When compared with those in KTP crystals, the shapes of these curves are almost the same in the two crystals. These imply that Nb doping does not significantly change the phase-matching properties of KTP crystals, even though it does largely change the phase-matching parameter of KTP crystals. These make Nb:KTP crystals more attractive in direct SHG of semiconductor laser radiation to produce blue coherent light     

蓝色荧光材料ZnMoO4:Ce4+的制备及光致发光研究

采用高温固相法成功合成了掺杂钼酸盐的ZnMoO4:Ce4+蓝色荧光材料。通过X 射线衍射（XRD）和荧光光谱等测试手段对所制备的材料的晶体结构和发光性能进行了表征。研究结果表明:实验按照理论化学计算比成功合成了ZnMoO4:Ce4+的蓝色荧光粉,该荧光粉为纯相的三斜结构;ZnMoO4:Ce4+在395 nm 处有强电子吸收,且在440 nm 处可发射高强度蓝光,其色坐标为（0.14,0.09）;此外,当Ce 含量为3 mol%时,荧光粉发光强度最佳。     

蓝色薄膜电致发光的新材料ZnO（S）：Ce^3＋的发光特性

介绍了新制备的TFEL发光材料ZnO(S)：Ce^3 ，测量了它的PL和EL特性，结果显示：这种材抖的TFEL为Ce^3 的发光，有较好的颜色组成(446nm，493nm)，可望用于监色TFEL.     

1341.4nmNd:YAP激光在KTP晶体中三倍频得到447.1nm蓝色相干辐射

本文报道用LiIO_3晶体将1341.4nmNd:YAP脉冲激光倍频产生的670.7nm辐射和1341.4nm激光在KTP晶体中和频得到447.1nm蓝色相干辐射。计算了上述非线性过程的相位匹配条件和有效非线性系数,计算与实验结果相当吻合。     

Fabrication of High-power White LEDs and White Light Uniformity Testing

As the blue and yellow lights are complementary colors, a blue InGaN LED chip is coated hy a yellow phosphor film to generate white light based on luminescence conversion mechanism. The emitted light of a blue LED is used as the primary source for exciting fluorescent material such as cerium doped yttrium aluminum garnet with the formula Y3Al2O12 ： Ce^3＋ （in short： YAG ： Ce^3＋ ）. The matching of the spectrum of the blue LED chips and the YAG ： Ce^3＋ yellow phosphor is studied to improve the conversion efficiency. The packaging methods and manufacturing processes for high power single chip-white LEDs are introduced. The uniformity of the output white light is investigated. Based on the characteristics of the high power white LEDs, some approaches and processes are suggested to improve the light uniformity when they are fabricated. The effectiveness of those approaches on the improvement of LEDs is discussed in detail and some interesting conclusions are also presented.     

Stable blue second-harmonic generation in a KTP waveguide with a diode laser in an external cavity

Stable second-harmonic generation from a diode laser, using a quasi-phasematching KTP waveguide and a grating in an external cavity is described. 1.35 mW of blue light was generated and the power fluctuation was less than 0.3%.<>     

蓝光LEDs的转换荧光粉发光效率的测量

本文研究了YAG:Ce荧光粉的色点红移的现象.当YAG晶格点阵中的Y被 Gd 激发或添加了Pr作为 Ce 的共同催化剂时就会发生这种现象.测量了在(Y,Gd)AG:Ce和YAG:Ce,Pr荧光粉样品内部的效率,其激发光线的波长为 470 nm.其结果表明这两种荧光粉的发光效率分别随着Gd和Pr聚集而降低.SrGa2S4:Eu.是另外一种常用的转换蓝光 LED 的颜色的荧光粉.室温下,这种荧光粉效率很高,理论上其发光效率比 YAG:Ce 的发光效率高出 33%.对这种荧光粉效率的测量结果表明其制作过程是影响性能的主要因素.将这种荧光粉印刷在放在-个或多个蓝光 LED 前面的屏幕的表面,测得其发光效率高达 364 lm/W.     

Generation of blue light at 469 nm by efficient frequency doublingof diode-pumped Nd:YAG laser

Efficient operation of a diode-pumped Nd:YAG laser at 938.5 nm is reported. A continuous wave output power of 3.9 W is obtained. Single-pass frequency doubling in periodically poled KTiOPO₄ (KTP) delivered a power of 88 mW at 469 nm. By intracavity frequency doubling an output of 200 mW in the blue region is achieved     

钛蓝宝石激光泵浦的Nd：YVO_4固体激光器

研究了用钛蓝宝石激光泵浦的Ｎｄ：ＹＶＯ４固体激光器的特性。得到基频连续激光输出功率为１９０ｍＷ，泵浦阈值为１３ｍＷ，光学斜效率为５１％。用ＫＴＰ晶体腔内倍频，得到二倍频激光输出功率为１０ｍＷ，总的光学转换效率为２．３％。给出了泵浦光波长（７４０～８３０ｕｍ）与激光输出功率之间的关系。