LD泵浦Nd:YAG微片激光器

ＬＤ泵浦Ｎｄ：ＹＡＧ微片激光器结构简单紧凑，与半导体激光器相比，前者具有激光线宽窄、光束质量好、相干长度长等优点，因此在一些测量领域有着较好的应用前景。目前对ＬＤ泵浦Ｎｄ：ＹＡＧ微片激光器的实验工作主要是获得单频、单模连续输出和线性频率调制特性研究。本文综述了近几年来ＬＤ泵浦Ｎｄ：ＹＡＧ微片激光器的研究方向、成果及应用，主要介绍了各国对ＬＤ泵浦Ｎｄ：ＹＡＧ微片激光器的调频特性的研究状况     

用于较大泵浦尺寸半导体泵浦固体激光器的一种特殊腔型

提出一种泵浦固体激光器的特殊腔型,解决了当功率较大时泵浦尺寸较大使得泵浦光斑与激光光斑不匹配的问题,并从激光腔理论和速率方程理论两方面通过数值计算验证了该腔型的优越性.同时对LD泵浦固体激光器以及倍频的设计提出了几条普适原则.     

Laser diode pumped LNYAB self-frequency-doubling lasers

The LNYAB self-doubling laser pumped by (LD) has been developed for the first time. The properties of the lasers are much better than those of NYAB self-doubling lasers pumped by LD. The LNYAB self-doubling laser pumped by LD can be operated in TEM_(00) mode with threshold pumping power of 3.6mW which is lower than that of LD pumped NYAB self-doubling lasers by 74%. The output power is 29mW at 0.531μm in green region with optical-to-optical efficiency of 4.8% which is higher than that of NYAB self-doubling laser by 20%.     

高能固态激光阵列光束合成技术浅析

建立了高能固态激光阵列合成的模型,对相干合成型和非相干合成型的高能固态激光系统进行了分析和比较.引入光束传输因子(BPF)作为评价合成光束的光束质量,对湍流大气对板条激光器和光纤激光器相干合成与非相干合成远场光束质量的影响进行了定量分析.计算模型和结果为工程实际中合成方案的选择和评估提供了参考.     

LD泵浦单频种籽激光器及其线宽的测试

研究了 L D泵浦的单频种籽激光器。以 Nd:YAG和 Nd:YL F晶体为工作介质 ,采用微片腔的谐振腔形式 ,获得了 1.0 6μm和 1.0 5 3μm的单频激光输出 ,其输出功率分别为 90 m W和 10 m W。采用光纤延迟自零差拍法测量了单频固体激光的线宽 ,其线宽为 30 0 k Hz。     

双端泵浦保偏光纤激光器

 以两台808 nm半导体激光器LD1和LD2为泵浦源,对光纤激光器双端泵浦进行了研究,获得了6.5 W的激光输出。实验分别测出了LD1和LD2半导体激光器单端泵浦和双端泵浦时的输出功率,对双端泵浦输出功率与单端泵浦功率之和进行了比较,利用双端泵浦提高了泵浦效率和输出激光功率。同时测量了输出激光的偏振度,通过计算得到双端泵浦输出激光的偏振度为0.5。     

高峰值266nm紫外激光器

报道了一种激光二极管(LD)端面泵浦的Nd:YAG声光Q开关高峰值功率266nm紫外激光器。该激光器采用紧凑的平平腔结构,LBO和BBO分别作为其二倍频和四倍频晶体。分别利用高偏振比LD阵列(40∶1)、低偏振比LD阵列(5∶1)及低偏振LD阵列腔内放置布氏片结构进行了实验。当注入功率为25W、调制频率为10kHz时,以上结构分别得到功率0.85,0.61和0.72W的266nm紫外光输出。其中,采用高偏振比LD阵列的输出功率最高,单脉冲能量为85μJ,脉宽为5ns,峰值功率高达17kW,泵浦光到紫外光的光-光转换率达3.4%。     

激光二极管泵浦Nd：FAP激光器

报道激光二极管泵浦的掺钕氟磷酸钙固体激光器，该器件在重复频率为１００Ｈｚ的准连续状态下运行，当耦合输出透过率为８％时，得到３１％的斜效率，比较了ＦＡＰ和ＹＡＧ这两种介质的激光器的性能，理论分析得出的两者的阈值泵浦功率的相对值与实验结果相一致，并证实ＦＡＰ是一种有前途的适合激光二极管泵浦的激光介质。     

Measurement of Thermal Lens Focal Length and Its Effect on Laser Output Characteristics in LD End-pumped Nd∶YVO_4 Lasers

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High efficiency passive mode-locked Nd:YVO<Subscript>4</Subscript> laser based on SESAM under direct pumping at 880 nm

We report on an 880 nm LD pumped passive mode-locked TEM₀₀ Nd:YVO₄ laser based on a semiconductor saturable absorber mirror (SESAM), with a high optical-to-optical conversion efficiency of 67.3%, and a slope efficiency of 71%. When the absorbed pump power was 11 W, 7.4 W average output power of 1064 nm continuous-wave mode-locked laser was achieved. To our knowledge, this is the highest optical-to-optical conversion efficiency among all the published reports of 880 nm LD pumped SESAM passive mode-locked lasers. The repetition rate of mode-locked pulse was 80 MHz with 26 ps pulse width. The maximum pulse energy and peak power were 92.5 nJ and 3.6 kW, respectively.     

Experiment Research on a Highly Stable LD-pumped Solid State Laser

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Experiment Research on a Highly Stable LD-pumped Solid State Laser

In high power laser systems, the stability of the seed laser is vitally important. This paper presents the work on the design and manufacture of a highly stable LD pumped solid state seed laser which has the advantages of being all solid state, compact, easy to manufacture and low cost. The laser was composed of two parts. One was an LD pumped 0.5 mm thin Nd: YLF laser system in which the instability was around±6% (3σ). The other was a close-looped laser power control system using external cavity power feedback. Using an electro-optic modulator, a 1×2 optical fiber splitter and a signal processing circuit, we successfully realized the highly stable LD pumped Nd: YLF laser in which the instability of laser output power was lower than±0.2 %/hour (3σ). A digital PID (Proportion, Integration and Differentiation) control method was used with a control frequency of 40 kHz. The 3 mW of highly stable laser power through the optical fiber was obtained.     

激光二极管端面纵向泵浦Nd:YVO_4激光器的热效应研究

针对激光二极管端面纵向泵浦Nd:YVO4激光器,本文理论和实验详细研究了Nd:YVO4晶体的热透镜效应。在激光二极管的中心波长分别为808nm和880nm及分别采用单端端面纵向泵浦和双端端面纵向泵浦结构情况下,实验测量了Nd:YVO4晶体的热透镜焦距,实验结果和理论预测基本吻合。同时在泵浦功率60W时获得了18.8W的连续基横模激光输出。     

Measurement of Thermal Lens Focal Length and Its Effect on Laser Output Characteristics in LD End-pumped Nd∶YVO4 Lasers

According to the resonator transform circle theory, the focal length of thermal lens of laser media in laser diode end-pumped solid-state lasers is analyzed and measured with a simple method. A 30W 808nm LD pumped YVO4 laser is developed and characterized.     

Measurement of Thermal Lens Focal Length and Its Effect on Laser Output Characteristics in LD End-pumped Nd:YVO4 Lasers

According to the resonator transform circle theory, the focal length of thermal lens of laser media in laser diode end-pumped solid-state lasers is analyzed and measured with a simple method. A 30W 808nm LD pumped YVO4 laser is developed and characterized.     

Alkali lasers for magnetic resonance imaging

Spin-polarized nuclei of such gases as ³He and ¹²⁹Xe are successfully used for magnetic resonance imaging of lungs and other organs of human body. To produce large numbers of spin-polarized nuclei required for this medical application, a high power narrowband tunable laser source is required. Diode pumped alkali lasers, developed during last several years can be an ideal source for this application. In this paper we present our latest achievements in diode pumped alkali lasers development. We describe optically pumped Cs laser tunable in the range of 14 GHz and operating in single transverse mode with a linewidth less than 3 MHz. We also present continuous wave diode pumped Rb and Cs lasers with output power 17 W and 20 W.     

激光二极管泵浦双频固体激光器

研制了0~1.5GHz频差的LD泵浦双频固体激光器。利用端面泵浦和F-P标准具的选模作用得到单频连续输出,在单频基础上将λ/4波片加入谐振腔中,造成本征光频率分裂,实现频差连续可调的双频激光输出。采用琼斯矩阵分析光在腔内的本征值及本征向量,实现了定量分析模在腔内的相位延迟和偏振状态,定量计算双频频差大小。     

双包层掺Yb3+光纤激光器的关键技术

大功率光纤激光器作为第三代激光器的代表,在激光加工和激光武器方面有着重要应用.介绍了掺Yb3+光纤激光器的发展历程,理论上分析了光纤激光器的泵浦阈值和输出功率,讨论了实验过程中涉及到的大功率LD泵浦、光纤耦合和双包层光纤等关键技术,为同类激光器的改进设计和深入研究提供参考.     

Characterization of laser processing of single‐crystal natural diamonds using micro‐Raman spectroscopic investigations

The application of lasers for processing diamond has revolutionized the diamond industry and its applications in microelectronics, microelectromechanical system (MEMS) and microoptoelectromechanical system (MOEMS) technologies. The process quality can be evaluated using spectroscopic techniques. In the present investigation, four different types of Q‐switched solid‐state lasers (with different beam parameters), namely, a lamp‐pumped Nd:YAG laser operating at 1064 nm, a lamp‐pumped Nd:YAG laser operating at second harmonically generated 532 nm, a diode‐pumped Nd:YVO₄ laser operating at 1064 nm and a diode‐pumped Nd:YAG laser operating at 1064 nm, have been employed for the processing of a single‐crystal, gem‐quality, natural diamond. The main objective behind the selection of these lasers with different beam parameters was to study the effect of wavelength, pulse width, pulse energy, peak power and beam quality factor (M² factor) on various aspects of processing (such as microcracking, material loss and cut surface quality) and their relative merits and demerits. The overall weight loss of the diamond and formation of microcracks during processing have been studied for the above four cases. The characteristics of the graphite formed during processing, elemental analysis, surface morphology of the cut surface and process dynamics have been studied using micro‐Raman spectroscopy and scanning electron microscopy (SEM). We observed that laser cutting of single‐crystal diamonds used for industrial applications can be accomplished without microcracking or surface distortion using Q‐switched Nd:YAG lasers. This allows direct processing without extensive postgrinding and polishing stages. Very efficient diamond processing is possible using diode‐pumped lasers, which results in the lowest possible breakage rate, good accuracy, good surface finish and low weight loss. From the micro‐Raman and SEM studies, it is concluded that the surface quality obtained is superior when diode‐pumped Nd:YVO₄ laser is used, owing to its extremely high peak power. The maximum graphite content is observed while processing with lamp‐pumped Nd:YAG laser at 532 nm. An overall comparison of all the laser sources leads to the conclusion that diode‐pumped Nd:YAG laser is a superior option for the efficient processing of natural diamond crystals. Copyright © 2006 John Wiley & Sons, Ltd.     

半导体可饱和吸收镜被动锁模侧面抽运Nd:YAG激光器研究

利用半导体可饱和吸收镜(SESAM)锁模技术实现的超快脉冲激光器具有结构简单紧凑、脉冲序列稳定等优势,在许多领域有着重要用途,自问世以来受到国内外的广泛关注.分析了SESAM被动锁模侧面抽运固体激光器的具体要求,进行了不同条件下的SESAM被动锁模侧面抽运Nd:YAG激光器实验.获得了最高平均功率9.5 W,脉冲重复频率71 MHz,单脉冲能量约141 nJ的皮秒激光脉冲.对SESAM被动锁模侧面抽运Nd:YAG激光器进行了实验和理论分析,对实现高功率连续超短脉冲激光器进行了探讨.