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71.
小极化子(Nb4+Li)荧光处于700—950 nm谱段,对不同化学还原程度同组分的纯铌酸锂晶体的研究表明荧光的强度反映了化学还原程度的强弱.从小极化子浅层能级出发,提出以“1中心3级态跃迁”来描述小极化子的受激荧光过程.钛扩散铌酸锂光波导(Ti:LiNbO3)表面还原程度的均匀性可能在波导制造的热扩散过程中被破坏.在对铌酸锂波导表面、深部的扫描结果中,荧光的强度呈现出表面与深部、波导内与外的差异,表面的强度是深部的6—8倍.研究表明,利用非损伤性的极化子荧光谱,对加工过程热处理进行检控是非常有效的.同时,波导内与外的荧光强度差异间接反映了波导的横切面的外形. 相似文献
72.
Dynamics of Efficiency Change by Temperature in Diode Pumped Nd:YAG Heat Capacity Laser 总被引:1,自引:0,他引:1 下载免费PDF全文
We investigate the influence of temperature on the efficiency of diode pumped Nd:YAG heat capacity laser is studied. It is shown that the efficiency of such a laser system is greatly reduced at higher temperature. This bad behaviour is mainly caused by the doped-ion redistribution among various Stark levels of the ground state, and by a thermal equilibrium between the upper laser level and the pump level. Meanwhile, the thermal excitations from the ground state to the lower laser level also play a role. We derive a model to describe those effects, with the considerations of emission spectrum of laser diodes, the subtle Stark structures and the linewidth of absorption and of simulated-emission. 相似文献
73.
A 2.048μm Tm,Ho:GdVO4 Laser Pumped Doubly Resonant Optical Parametric Oscillator Based on Periodically Poled Lithium LiNbO3 下载免费PDF全文
A multi-grating periodically poled LiNb03 (PPLN) doubly resonant optical parametric oscillator (DROPO) pumped by a 2-ttm laser is demonstrated experimentally. Employing acousto-optically Q-switched Tm,Ho:GdV04 laser with pump pulse of 25ns and repetition rate of lOkHz as pump sources firstly, the noncritically quasi- phase-matched (QPM) tunable mid-IR output in 3.87-4.43 μm is produced. Wavelength tuning is achieved with crystal temperature tuning from 50-180^o C. When the incident average pump power is 3 W at 2.048μm, the total OPO output power of 195mW at wavelength 3.88μm is obtained, corresponding to optical-to-optical conversion efficiency up to 6.5%. 相似文献
74.
Orthogonally Linearly Polarized Dual Frequency Nd:YAG Lasers with Tunable Frequency Difference and Its Application in Precision Angle Measurement 总被引:2,自引:0,他引:2 下载免费PDF全文
The orthogonally linearly polarized dual frequency Nd: YA G lasers with two quarter wave plates in laser resonator are proposed. The intra-cavity variable birefringence, which is caused by relative rotation of these two wave plates in laser inner cavity, results in the frequency difference of the dual frequency laser also changeable. The theory model based on the Jones matrix is presented, as well as experimental results. The potential application of this phenomenon in precision roll-angle measurement is also discussed. 相似文献
75.
Magnetic properties and nanostructures of FePtCu:C thin films with FePt underlayers (ULs) are studied. The effect of FePt ULs on the orlentation and magnetic properties of the thin films are investigated by adjusting FePt UL thicknesses from 2nm to 14nm. X-ray diffraction (XRD) scans reveal that the orientation of the films is dependent on FePt UL thickness. For a 5-nm FePtCu:C nanocomposite thin film with a 2-nm FePt UL, the coercivity is 6.S KOe, the correlation length is 59 nm, the desired face-centred-tetragonal (fct) ordered structure [Llo phase] is formed and the c axis normal to the film plane [(001) texture] is obtained. These results indicate that the beffer orientation and magnetic properties of the films can be tuned by decreasing the thockness of the FePt UL. 相似文献
76.
在LiNbO3中掺进0.015mass%MnCO3和 0.1mass%CeO2,以Czchralski法生长Li/Nb比为1.38的近化学计量比Ce∶Mn∶LiNbO3(Ce∶Mn∶SLN)晶体和Li/Nb比为0.946的同成分Ce∶Mn∶LiNbO3(Ce∶Mn∶CLN)晶体.测试了晶体的红外光谱和紫外可见吸收光谱,讨论了Ce∶Mn∶SLN晶体OH-吸收峰和吸收边移动机理.利用二波耦合光路测试了晶体的指数增益系数,Ce∶Mn∶SLN晶体指数增益系数Γ达到27 cm2-.同时,研究了Ce∶Mn∶SLN指数增益系数提高的机理. 相似文献
77.
78.
MinhuaJiang YuliaTian JianhuaJiang WanxiaHuang JiyangWang Xiao 《北京同步辐射装置》2001,(2):131-137,
Pure and neodymium-doped gadolinium calcium oxoborate crystals of high quality were grown by the Czochralski method.The orientation of crystal was precisely determined,and the samples for measurements were prepared.Through synchrotron x-ray topography and high-resolution x-ray diffractometry,the twin structure was discovered.Some properties such as the figure of merit value,and dielectric,piezoelectric,and elastic constants were meausured along with a discussion of the anisotropy of the laser properties. 相似文献
79.
纳米荧光粒子YVO_4∶Eu的合成及其在指纹显现中的应用 总被引:1,自引:0,他引:1
以柠檬酸为络合剂,在水相中合成了悬浮稳定性较好的稀土YVO4∶Eu溶胶,采用XRD、TEM、荧光光谱等技术,研究了稀土荧光粒子的尺寸、形貌、晶胞参数及发光性能.结果表明合成的YVO4∶Eu荧光粒子为四方晶系,粒径约为10nm,分散性较好;在pH=9.0时合成的Y0.7VO4∶Eu0.3溶胶具有最大的荧光强度,其最大发射峰在619nm;经乙二胺四乙酸二钠表面修饰后的Y0.7VO4∶Eu0.3纳米荧光粒子能够清晰地显现出光滑客体上的指纹,颜色为红色. 相似文献
80.