HPVB法Fe^(2+):ZnSe激光晶体生长及激光输出特性

本文采用纯度为99.999%的颗粒状ZnSe为基质材料,纯度为99.998%的FeSe粉末为掺杂物,通过HPVB法生长了Fe^(2+):ZnSe晶体,晶体尺寸达Φ50.8 mm×120 mm。采用电感耦合等离子发射光谱仪测试了Fe^(2+):ZnSe晶体样品中铁离子掺杂浓度为3.048×10^(18)cm^(-3)。采用粉末XRD衍射仪测试了Fe^(2+):ZnSe晶体样品的X-射线衍射谱,其衍射谱与基质ZnSe样品衍射谱匹配度达92%。采用UV/VIS/NIR分光光度计和傅里叶红外光谱仪测试了Fe^(2+):ZnSe晶体样品的透过谱图,透过谱在波长3.0μm处出现了明显的Fe^(2+)离子吸收峰。采用2.94μm Er:YAG激光器为泵浦源抽运尺寸为10 mm×10 mm×4 mm的Fe^(2+):ZnSe晶体样品,重复频率为100 Hz时,激光能量输出达12 mJ,输出波长调谐范围3.95~4.15μm。

Fe^(2+)∶ZnSe激光晶体光学吸收及激光输出性能

采用热扩散掺杂技术制备了Fe2+∶ZnSe晶体,测试晶体样品中铁离子浓度达1.27×1018cm-3。分析了Fe2+∶ZnSe晶体光谱的光学吸收特性,在室温条件下,采用2.90μm激光器泵浦Fe2+∶ZnSe晶体,获得了中心波长4.45μm,平均功率67 mW的中红外激光输出。

室温脉冲Fe^(2+):ZnSe中红外激光特性研究

处于3~5μm波段的激光源在遥感、环境保护、医疗、通信和红外对抗等民用和军用领域都有广阔的应用前景。Fe^(2+):ZnSe晶体由于在材料特性和光学特性等方面都具有明显优势,是3~5μm波段极具潜力的激光介质之一。在室温条件下利用自制非链式脉冲HF激光器作为泵浦光源,对晶体直径为10 mm,厚度1 mm,Fe^(2+)离子掺杂浓度为3×1019/cm3的Fe^(2+):ZnSe晶体进行了研究,获得了中心波长4 295 nm、最大输出能量78.8 mJ的中红外激光输出。输出激光能量相对于晶体吸收泵浦能量的转换效率为27.7%,斜率效率达28.8%。采用小角度(3°)斜入射的方案很好地解决了Fe^(2+):ZnSe激光器谐振腔镜镀膜问题。

Fe∶ZnS/ZnSe中红外固体激光器研究进展

高性能中红外激光在军事对抗、生物安全、环境科学等领域有重要的应用价值。Fe∶Zn S/Zn Se具有长输出波长、宽吸收带和发射带的特点,是实现高性能、宽调谐3μm^5μm激光输出的最有效激光介质。介绍了Fe∶Zn S/Zn Se的光谱和热动力学特性,评述了Fe∶Zn S/Zn Se在低温和常温下激光输出性能方面的最新进展,分析了Fe∶Zn S/Zn Se激光器在功率、能量提升以及室温运转方面面临的科学挑战。

Fe^(2+):ZnSe晶体制备及光学吸收

本文采用热扩散掺杂技术制备了Fe2+∶ZnSe晶体,获得尺寸达20 mm×2.0 mm的晶体样品。光谱测试分析结果显示,晶体样品在3.0μm附近具有显著的Fe2+∶ZnSe晶体的特征吸收,相对吸收强度达85%;通过ICP-AES测试该晶体样品中铁离子为4.5×1017cm-3;分析了影响掺杂铁离子浓度的主要因素。

ZnSe∶Fe^(2+)中的动态Jahn-Teller效应和远红外光谱的研究

推导了 3d4 / 3d6离子基态 5D在立方晶体场、自旋 轨道耦合和动态Jahn Teller效应作用下的哈密顿矩阵 ,并用对角化该哈密顿矩阵的方法研究了Fe2 + 在ZnSe中的远红外光谱 ,理论计算与实验符合得好 .研究表明 ,在ZnSe∶Fe2 + 中 ,比晶体场理论分析多出的分裂谱线是Fe2 + 与ZnSe晶格间的动态Jahn Teller效应引起的 .还预测了其它Jahn Teller效应分裂谱 .所推导的哈密顿矩阵对研究 3d4 / 3d6离子在立方晶体中的精细光谱、电子顺磁共振谱和动态Jahn Teller分裂都是有用的 .

中红外Fe^(2+):ZnSe激光器研究进展

发光谱位于3~5μm大气窗口处的中红外激光在医疗、工业加工、大气遥感、空间通讯、红外对抗等领域具有广泛的应用前景。以过渡金属(TM)掺杂Ⅱ~Ⅵ族硫化物晶体作为增益介质的激光器件可实现中红外激光输出,其中Fe^(2+):ZnSe激光器具有转换效率高、中红外波段可调谐范围宽、结构紧凑等优点,是中红外波段实现高功率、高能量、短脉冲的最有效途径之一。随着近些年材料技术的发展,Fe^(2+):ZnSe激光器发展迅速,逐渐成为热点之一。本文综述了以Fe^(2+):ZnSe激光器为代表的TM^(2+):Ⅱ~Ⅵ族激光器的发展历程,介绍并分析了Fe^(2+):ZnSe增益介质的制备方法,讨论了影响Fe^(2+):ZnSe激光器性能的泵浦源及因素,综合评述了Fe^(2+):ZnSe激光器的输出特性,总结了Fe^(2+):ZnSe激光器在室温和超短脉冲方向上的最新进展,并展望了Fe^(2+):ZnSe激光器后续可能的发展方向。

Cr^(2+):ZnSe全固态中红外激光器

建立了一种高质量、高效率全固态中红外激光系统,并对激光输出的效率、光束质量等指标进行了测试。首先,以二极管激光器为泵浦源,Tm^(3+):YAP晶体为增益介质,搭建了输出波长为1.97μm的近红外激光器。然后,以Tm^(3+):YAP激光器为泵浦源,自行开发研制的Cr^(2+):ZnSe单晶为增益介质,搭建了全固态中红外激光器。最后,测试了全固态中红外激光器的光束质量及激光器出光效率,并对谐振腔光效率的理论输出值与实际的激光器出光参数进行了对比。实验结果表明:此全固态中红外激光器的光光转换效率为17.2%,斜率效率为20%,在最高输出能量为3 W时的光束质量(M^2)在x和y方向分别为1.7和1.73,光束基本为圆形的高斯光斑。

高温高压制备Cr^(2+):ZnSe单晶及其光学性质

为了得到高质量、大尺寸Cr2+∶Zn Se中红外激光晶体,以适应高功率全固态中红外激光器的发展要求,在高温高压下全石墨腔内运用布里奇曼晶体生长方法,生长出了高质量Ф30×120 mm Cr2+∶Zn Se单晶。采用X射线粉末衍射(XRD)、透射电镜(TEM)、红外稳态吸收及荧光光谱等测试方法对晶体的结构及光谱特性进行了表征,并探讨了Cr2+∶Zn Se晶体中Cr2+的能级结构及跃迁机理。结果表明:所生长的Cr2+∶Zn Se单晶结构均匀,性质稳定,1.97μm激发的荧光光谱覆盖1.9~3μm范围,可用于获得2~3μm全固态中红外激光。

连续波HF激光泵浦Fe^(2+):ZnSe激光器的可行性

针对目前Fe^(2+):ZnSe激光器缺乏有效的高功率泵浦源这一关键瓶颈,提出了采用连续波HF化学激光器泵浦Fe^(2+):ZnSe来实现4μm波段激光输出的技术路线,结合实验和理论手段考察了此技术路线的可行性。首次获得了由连续波HF化学激光泵浦的Fe^(2+):ZnSe激光器的W级激光输出,输出功率约为1.7 W,谱线峰值波长为4.18μm,出光时间约2 s。

基于Fe^2＋：ZnSe粉末的4．45μm中红外随机激光

利用Fe^(2+):ZnSe微米粉末产生了4. 45μm的中红外随机激光。通过气相热扩散法制备了Fe^(2+)离子掺杂的ZnSe多晶块体,将制得的块体研磨成尺寸在10～50μm的微米粉末。X射线衍射(XRD)结果表明这些Fe^(2+):ZnSe粉末具有与ZnSe块体相同的立方闪锌矿结构,Fe^(2+)离子的引入没有改变ZnSe的晶体结构。在2. 94μm的脉冲激光泵浦下,研究了室温下Fe^(2+):ZnSe粉末的光致发光特性和发光脉冲的时间特性。随着泵浦能量增加,光谱发光强度发生跃变,光谱线宽从500 nm减小到50 nm,脉冲时间从270 ns减小到50 ns。当泵浦能量高于2 m J/pulse的阈值时,观察到中心波长4. 45μm的中红外随机激光。这种中红外随机激光器在红外标记、光通信、分子光谱测量等领域有很好的应用前景。

双温区热扩散掺杂Fe^(2+)∶ZnSe激光晶体的制备及激光输出性能

本文以CVD ZnSe晶片为基质材料,以FeSe粉末为掺杂物,采用双温区热扩散掺杂技术获得了尺寸为ϕ22 mm×4 mm的Fe^(2+)∶ZnSe激光晶体。通过二次离子质谱(SIMS)测试该晶体样品表面铁离子浓度为3.43×10^(18) cm^(-3),并通过X射线光电子能谱(XPS)分析了晶体样品中铁元素的离子价态。采用UV/Vis/NIR分光光度计和傅里叶红外光谱仪测试了Fe^(2+)∶ZnSe激光晶体的透过谱图。测试结果显示,在3.0μm处出现了明显的Fe^(2+)吸收峰,峰值透过率为5.5%。以波长为2.93μm的Cr,Er∶YAG激光器为泵浦源,温度77 K时抽运尺寸10 mm×10 mm×4 mm的Fe^(2+)∶ZnSe晶体,获得了能量为191 mJ、中心波长4.04μm的中红外激光输出,光光转换效率13.84%。

ns脉冲激光诱导制备铬掺杂ZnSe纳米粒子独特的生长以及光学特性

在液相环境中，利用纳秒（ns）脉冲激光器轰击消融铬掺杂ZnSe（Cr^2＋：ZnSe）微米颗粒，制备出Cr^2＋：ZnSe纳米粒子，扫描电镜以及X射线衍射检测，结果显示，制备所得的粒子为平均尺寸为50nm的ZnSe闪锌矿结构纳米粒子。基于Cr^2＋：ZnSe纳米粒子，观察到中心波长为2180nm、阈值为0．4mJ／pulse的随机激光效应。相比于Cr^2＋：ZnSe晶体激光器，纳米粒子随机激光的中心波长发生了约170nm的蓝移，Cr^2＋：ZnSe纳米粒子的光致发光寿命也比Cr^2＋：ZnSe晶体要短。

Nanocrystallization of Amorphous Fe_(73.5)Cu_1Nb_3Si_(13.5)B_9 Irradiated by Laser

The surface nanocrystallization of amorphous Fe73.5 Cu1Nb3Si13.5B9 radiated by CO2 laser was studied by means of M（oe）ssbauer spectroscopy, transmission electro iroscope and X-ray diffraction. The result shows that under certain technical conditions, nanocrystalline is fiound on the surface of amorphous Fe73.5 Cu1Nb3Si13.5B9 radiated by laser; the crystallization phase is α-Fe（Si） crystalline, and its size is about 10-20 nm; the nanocrystalline is uniformly distributed on amorphous base to keep the amorphous and crystallized phase in balance; the a mount of crystallization reaches 23% when the laser power is 300 W, the diameter of light spot is 20 mm, and the radiation speed is 20 mm/s. The phase balance can be controlled by adjusting the laser technology parameter. Laser radiation on the amorphous Fe73.5 Cu1Nb3Si13.5B9 alloy is an important technique for surface nanocrystallization of the amorphous alloys.

Nonlinear Change in Refractive Index and Transmission Coefficient of ZnSe:Fe²⁺at Long-Pulse 2.94-μm Excitation

An experimental study of the nonlinear changes in refractive index and transmission coefficient of single-crystal ZnSe:Fe2+, fabricated through the Fe-diffusion method, at long-pulse (~300 ns), sub-mJ, 2.94-mm Z-scan probing is reported. As well, a theoretical model based on the generalized Avizonis-Grotbeck equations is developed and applied for straightforward fitting of the open- and closed-aperture Z-scans, obtained for ZnSe:Fe2+ with different Fe2+ centers concentrations. The modeling results reveal that the contributions in the absorption and refractive index nonlinearities of ZnSe:Fe2+ are “common” resonant-absorption saturation (the minor part) and pulse-induced heating of the samples (the major part), which are strongly dependent on Fe2+ concentrations. Large values of the index change (>~10-3) and partial resonant-absorption bleaching (limited by ~50%), both produced via the thermal effect mainly, are the features of the ZnSe:Fe2+ samples inherent to this type of excitation.

Thermoelectric Simple and Multilayers Prepared by Laser

Thermoelectric layers as Bi2Te3, Yb0.19Co4Sb12, FeSb2Te, Ce0.1Fe0.7Co3.3Sb12 and FeSb2Te/Ce0.1Fe0.7Co3.3Sb12 multilayers were prepared by Pulsed Laser Deposition (PLD). Smooth, nano-crystalline, stoichiometric layers were synthetized in a classical PLD arrangement or in a special off-axis PLD arrangement, followed by Rapid thermal annealing. Results of physical characterizations such as morphology—Atomic Force Microscope, Scanning Electron Microscope, composition-Energy Dispersive X-ray analysis, crystallinity—X-ray Diffraction, separation of multilayers—Secondary of ion beam mass spectroscopy SIMS and study of thermoelectric properties such as the thermoelectric figure of merit ZT, in-plane electrical resistivity, Seebeck coefficient and thermal conductivity are presented. For thermal conductivity measurement a newly developed Atomic force thermal microscope (AFMTh) was tested. Results obtained on the single layers compared to multi-layered structures are discussed.

Modeling and analysis of actively Q-switched Fe:ZnSe laser pumped by a 2.8μm fiber laser

A theoretical model concerning active Q-switching of an Fe:ZnSe laser pumped by a continuous-wave(CW)2.8μm fiber laser is developed.Calculations are compared with the recently reported experiment results,and good agreement is achieved.Effects of principal parameters,including pump power,output reflectivity,ion concentration and temperature of crystal,on the laser output performance are investigated and analyzed.Numerical results demonstrate that similar to highly efficient CWFe:ZnSe laser,low temperature of the crystal is significant to obtain high peak power Q-switched pulses.The numerical simulation results are useful for optimizing the design of actively Q-switched Fe:ZnSe laser.

Widely tunable passively Q-switched Er3+-doped ZrF4 fiber laser in the range of 3.4–3.7 μm based on a Fe2+:ZnSe crystal

We report the first(to the best of our knowledge) tunable passively Q-switched Er3+-doped ZrF4 fiber laser around 3.5 μm. In this case, a Fe2+:ZnSe crystal is used as the saturable absorber, and a plane-ruled grating in a Littrow configuration acts as the tuning element. At the tuned wavelength of 3478.0 nm, stable Q-switching with a maximum average power of 583.7 mW was achieved with a slope efficiency of 15.2% relative to the launched 1981 nm pump power. Further power scaling is mainly limited by the available 1981 nm pump power. The corresponding pulse width, repetition rate, and pulse energy are 1.18 μs, 71.43 kHz, and 7.54 μJ, respectively. By rotating the grating, the Q-switching can be continuously tuned in the region of 3.4–3.7 μm. To the best of our knowledge, this is the first pulsed rare-earth-doped fiber laser tunable in the region beyond 3.4 μm.

中波红外激光技术最新进展

3～5μm中红外波段激光源是近年来备受国内外关注的研究热点,本文综合评述了产生中红外波段激光的5种主要方法(CO2激光倍频技术、泛频CO激光技术、光学参量振荡器、氟化氘激光器、Fe2+∶ZnSe固体激光技术)的国内外发展现状,总结分析了各种方法的关键技术和存在的问题,指出了该技术的未来发展趋势。

中红外固体激光器研究进展

本文介绍了中红外固体激光器中新型的Fe^2＋∶Zn Se激光器和基于Mg O∶PPLN、Zn Ge P2晶体的光参量振荡器的发展现状,讨论了它们在发展过程中遇到的技术难题,探讨了中红外固体激光器的未来发展方向。波长为3~5μm的中红外固体激光器具有效率高、体积小和重量轻等优点,在工业、医疗、军事等方面具有重要应用价值,研制大尺寸、高质量中红外激光晶体和输出波长更长的红外高功率激光泵浦源已成为中红外固体激光器未来发展方向之一。