三元磷酸氧碲晶体的生长

采用提拉法按照不同的原料配比(P_2O_5的摩尔分数分别为14.0%,16.0%,20.0%,22.0%,25.0%和33.3%),生长出Te_8P_4O_(26)、Te_3P_2O_(11)和Te_2P_2O_9,3种新的磷酸氧碲晶体。确定了提拉法生长晶体的生长参数;介绍了3种晶体的结构;表征了3种晶体的热性能与红外光谱;计算了晶体中磷氧四面体的扭曲程度和偶极矩;探究了磷氧四面体的对称性与红外光谱中P–O振动峰的简并性之间的关系。结果表明:3种晶体都是纯相晶体且没有杂质存在;Te_8P_4O_(26)和Te_3P_2O_(11)在加热过程中存在相变或不一致熔融,而Te_2P_2O_9一致熔融;随着磷氧四面体(PO4)对称性的增加,红外光谱中P–O振动峰的简并性增加。     

Growth, structural, thermal properties and spectroscopic characteristics of KTb（WO4）2 single crystal

KTb(WO4)2(KTW) single crystal with dimensions up to 30mm×30mm×10mm was grown by the top-seeded solution growth (TSSG) method for the first time. The crystal structure was refined at room temperature by using single crystal X-ray diffraction data. Absorption and fluorescence spectra were measured at room temperature. The fluorescence lifetime of KTb(WO4)2 was 114μs. The specific heat of the KTb(WO4)2 crystal was also measured at room temperature.     

Optical-transition properties of the Nd3+ ion in KLu(WO4)2 crystal

Optical absorption and emission intensities of Nd3+ ion in KLu(WO4)2 crystal were investigated. Based on the Judd-Offelt theory, we calculated the following spectral parameters: phenomenological intensity parameters Ω2=5.567×10–20, Ω4=3.597×10–20, and Ω6= 3.800×10–20 cm2. The radiative lifetime of levels 4F3/2 was 182.58 μs. The fluorescence branching ratio for the transition 4F3/2→4I11/2 was 46.98%. In addition, the radiative transition probabilities AJ,J’, oscillator strengths PJ,J’ and the values of inte...     

Growth and characterization of ferroelectric Tb2（MoO4）3 crystal

By using Zb4O7 and MoO4 as starting materials, ferroelectric Tb2(MoO4)3 crystal was grown by the Czochralski method. The as-grown crystal was pale green color, transparent and crack-free. X-ray powder diffraction (XRPD), transmission spectrum, dielectric con-stant and polarization-electric field (P-E) hysteresis loop measurements were performed to characterize the crystal. The XRPD confirmed the as-grown crystal to be Tb2(MoO4)3. The transmission spectrum of the crystal showed that its transmittance in the entire visible and most near-infrared region was more than 70% except for an absorption peak around 486 nm. Obvious dielectric anomaly could be observed at low frequencies with increasing temperature through the dielectric constant measurement and the Curie temperature of Tb2(MoO4)3 crystal was determined to be 162.3℃. The unsaturated P-E hysteresis loops indicated that it was difficult for the ferroelectric domains in Tb2(MoO4)3 crystal to array regularly with repeated switching of the electric field.     

SrWO4晶体的紫外受激拉曼散射

使用提拉法生长了高光学质量的SrWO₄晶体,尺寸为22mm×40mm,重72.3g.测量了SrWO₄ 晶体的透过光谱,其短波截止边为263nm,长波截止边大于3200nm,因此可在较宽波长范围内实现拉曼频移.采用无腔的单次通过方式,在SrWO₄晶体中实现了紫外光激发的受激拉曼散射.当抽运光为355nm皮秒激光脉冲时获得了3级斯托克斯谱线（366.44、379.25、392.98nm）,其中一级斯托克斯线的抽运阈值仅为169.76MW/cm²,相应的拉曼增益高达49.09cm/GW.实验表明,SrWO₄具有透光波段宽、抗光损伤能力强、拉曼阈值低、增益系数大等优点,在紫外激光的拉曼变频方面表现出良好应用前景.     

CIS太阳电池材料的研究进展

综述了国内外太阳电池及其材料的发展概况.目前应用的光电转换材料主要有硅材料和化合物半导体材料,介绍了用这几类材料制作的太阳电池的特点,重点介绍了其光电转换效率.在薄膜电池材料中重点综述了铜铟硒(CIS)基薄膜太阳电池的研究进展.由于制约太阳电池发展的关键问题是制备成本高和转换效率低,提出了采用化学法制备CIS基薄膜材料及其梯度带隙,该方法将开辟高性能CIS基吸收层薄膜材料及其器件制备的低成本新途径.     

SiC单晶片的超精密加工

半导体晶片的加工质量和精度,直接影响到器件的性能.本文提出了一种超精密加工SiC晶片的方法,并详细论述了化学机械抛光的原理.加工后的SiC单晶片,平整度为±3μm,粗糙度＜5nm,且应力较小.     

新型激光自倍频Yb:YAB晶体的性质研究

采用助熔剂法生长了不同配比的激光自倍频晶体Yb:YAl3(BO3)4(Yb:YAB).测量了晶体的室温吸收谱和荧光光谱,室温下仅存在一个吸收带,主吸收峰在976nm处,能与InGaAsLD有效耦合.在1.03μm处存在一个强荧光峰.测定了晶体的热膨胀系数,在平行与c轴方向的热膨胀系数较大,α2=9.4×10-6/K,约为a轴方向的3.5倍.在10％的Yb:YAB晶体中,以入射功率为11W,波长为977nm的光纤耦合二极管激光器泵浦得到4.3W的基频光波输出,斜效率为48％;在同样实验条件下得到了1.1w的自倍频绿光输出,总转换效率为10％.     

激光二极管抽运Nd∶GdVO_4微片激光器

报道了一种新型激光二极管(LD)端面抽运Nd∶GdVO4微片激光器,测量了抽运输入功率与激光输出功率的关系,激光阈值功率为83 mW,在2 W的抽运功率下得到860 mW的1.064μm基横模连续激光输出,光-光转换效率为43%,最大斜度效率达到47%。     

新型BiB3O6晶体高效和频产生355 nm紫外激光

报道了新型高效BiB3 O6晶体优良的非线性光学性能 ,给出了蓝紫外波段的相位匹配曲线。将该晶体用于纳秒电光调Q的Nd∶YAG激光器中 ,对基波 (10 6 4nm)及其倍频光 (5 32nm)进行和频得到了转换效率为 19 2 %的 35 5nm紫外激光输出 ,高于相同条件下用BBO晶体作为三倍频晶体的结果