基于光线追迹的闪光灯泵浦激光聚光腔的结构优化

聚光腔是灯泵固体激光的重要部件,主要作用是最大限度地将泵浦光能聚集到激光棒上的同时,尽可能使激光棒获得均匀的泵浦。为了实现灯泵固体激光器大能量输出,需考虑优化激光聚光腔,提高其泵浦效率。通过以蒙特卡洛离散方法为核心的光线追迹技术和合理的模型建立,以四灯为例,研究了对确定直径的激光棒,泵浦效率随构成腔体的椭圆长短轴比(a/b)的变化,以及同样的长短轴比下,泵浦效率随泵浦灯直径的变化。得到了在确定直径的激光棒和泵浦灯下,泵浦效率最高的椭圆长短轴比例。此外,研究了对确定直径的激光棒在不同直径泵浦灯的情况下,泵浦均匀性随椭圆长短轴比a/b的变化。     

钕玻璃、YAG激光棒长于椭圆腔的实验结果

在[1～4]中,我们报道了长脉冲和调Q脉冲钕玻璃、YAG固体激光器,激光棒长于椭圆腔(灯弧长),比棒与椭圆腔(灯弧长)相等时,能进一步降低阈值,提高输出效率的实验结果。 本文用测量椭圆聚光腔外左右两端、沿加长棒的轴线方向泵浦光能分布规律的方法,对这个问题深入进行了探讨。     

重复率运转的闪光灯泵浦掺钛宝石激光器研究

本文简述闪光灯泵浦的掺钛宝石激光器的发展状况和应用前景，描述了我们研制成功的实用型四灯泵浦的掺钛宝石激光器实验装置和实验结果．实验中采用本单位生长的掺钛宝石棒尺寸为φ１００×１６０ｍｍ，有效泵浦长度为１５２ｍｍ；平凹激光谐振腔，腔长３５ｃｍ；自制的四灯聚四氟乙烯聚光筒，漫反射效率９８％；四灯串联泵浦，闪光脉宽为１０μｓ．当输入能量为３２０Ｊ时，激光输出达到１．７Ｊ，激光效率０．６％，重复频率１Ｈｚ，可调谐范围７００～１０００ｎｍ．     

钕玻璃固体激光器棒长于椭圆腔的实验

一、引言 在常用的中小型固体激光器中,大都采用直管泵浦灯和椭圆聚光腔。为了更好地利用泵浦光的能 量,无论是在理论分析上,还是在实际应用上,都认为应该是使激光棒、直管灯和椭圆腔三者的长度相等。     

专利之页

一种液体冷却的固体激光器激光头邓仁亮(北京工业学院) 本发明的结构实现对激光棒,泵浦灯和紧包漫反射泵浦腔的混合冷却,流经激光棒的冷却剂成陀螺状湍流流动,取得了比原有冷却方式更好的冷却效果,结构紧凑。     

圆锥形激光泵浦腔

众所周知,椭圆柱面腔不是理想的激光泵浦结构。灯和棒的冷却套引起光线偏离,破坏了泵浦源的圆对称性。椭球和球则可避免这种轴的畸变。但是它们沿轴产生不均匀的象。在此情况下,我们研究了由两个面对面放置的圆锥组成的泵浦腔,看看这种结构是否兼有好的径向成象能力和好的轴向均匀性,是否容易制造,也就是说,看看是否能用它代替上面的腔。     

比较用于泵浦掺钕钇铝石榴石激光器的氪灯与氙灯

已使充气压力在450乇与4个大气压之间的直管氪、氙闪光灯（膛径6毫米,电弧长3吋）在单椭圓镀金泵浦腔内运转,从而激励摻钕钇铝石榴石激光棒(直径0.25吋,长3吋）。本文叙述了输入电能由2到40焦耳（脉沖持续期120微秒）,脉沖重复率由单脉沖到20赫时,激光器运转与灯的充气压力间的函数关系。已发现除非在电流密度高的情况下,用氪灯泵浦摻钕钇铝石榴石激光器一般比用氙灯好。特别是对于那些参量适于商品与军事应用的系统来说,氪灯的最佳充气压力约为700乇,而氙灯最佳充气压力约为1000乇。使用压力为700乇的氪灯时,阈值是使用压力为1000乇氙灯时的58%;交叉能量（对相同的绝对效率来说）是40焦耳输入,此值相当于我们系统中约375毫焦耳之输出。     

空腔灯泵浦激光器

本文叙述了用空腔(同轴)灯来泵浦圆柱棒钕玻璃的空腔灯泵浦激光器的实验装置与测试结果,并把它们与常用的椭圆聚光罩直管灯泵浦激光器的实验结果进行了比较.     

加长棒脉冲钕玻璃激光器的阈值,效率实验研究

本文从实验方面研究了加长激光棒使其长于椭圆泵浦腔时，对脉冲钕玻璃激光器输出性能的影响。实验结果发现：在相同条件下，激光棒适当长于椭圆泵浦腔，与棒和椭圆泵浦腔相地相比，能降低泵浦阈值，提高输出效率。     

Nd：YAG激光器最佳泵浦条件的实验研究

本文报导不同泵浦腔的比较及几何传输效率的数值计算．研究泵浦腔几何尺寸，灯的类型，反射膜层与泵浦效率的关系．并讨论泵浦均匀性及灯放电回路对泵浦效率的影响．     

Simple 1 micron ring laser oscillators pumped by fiber-coupledlaser diodes

We have designed simple nonplanar Nd:YAG ring laser oscillators that utilize all flat mirrors and are pumped by the fiber-coupled output from ten 3 watt diode lasers. We have obtained up to 8.5 W at 1.06 microns of diffraction-limited, single frequency output with no measureable astigmatism or ellipticity with a total pump power of 26 W from a pair of 400 micron diameter fibers. Convex curved surfaces on the Nd:YAG rod are used to increase the cavity mode size at the rod while minimizing the contribution of aspheric thermal lensing. Comparison to a linear cavity with no intracavity polarizing element indicates that stress depolarization is a significant loss mechanism in the ring laser. The cavity design is also suitable for use with birefringent laser media, such as Nd:YLF or Nd:YVO₄     

Modeling of longitudinally pumped CW Ti:sapphire laser oscillators

Longitudinal pumping of CW Ti:sapphire oscillators is considered to predict the power output of such oscillators using folded, astigmatically compensated cavities. The model predicts how the oscillator performance is affected by the selection of Ti³⁺ concentration, material figure of merit, rod length, and pump and cavity mode waists. Experimental results for broadband CW oscillators pumped by CW argon ion lasers are reported, and these are shown to be in excellent agreement with theory. Nearly 30% slope efficiency is achieved with a four-mirror folded cavity and even higher efficiencies are predicted for optimized pumping     

LED end-pumped Nd:YAG lasers

Experimental results are reported on the room-temperature operation of Nd:YAG lasers end pumped with an LED. The radiation from a 10-percent-efficient 0.46-mm-diam domed LED was coupled to the end of a 0.46-mm-diam × 5.0-mm-long laser rod with a large hemispherical reflector. At 20°C, a multimode laser power of 0.25 mW was obtained at an LED current of 250 mA. By measuring the variation of threshold pump power with rod temperature and the laser power versus pump power just above threshold, both the laser cavity loss and the output mirror transmission were determined. A round-trip cavity loss as low as 0.022 percent was measured. A calculation of the fractional pump power absorbed in the rod for the LED spectrum gave 56 percent for a 5-mm-long rod while measurements showed that 30 to 35 percent of the LED power was being absorbed indicating an LED-to-laser rod coupling efficiency of 54 to 63 percent for this arrangement. With such efficient absorption of pump power and low cavity loss, end-pumped Nd:YAG lasers with high slope efficiencies above threshold are possible.     

Optimization of pumping conditions in end pumped Tm:YAP lasers with the consideration of thermal effects

In this work, we presented the measurements and calculations for the optimal pump conditions and their effects on thermal lens, fracture limit and laser efficiencies of end pumped Tm-doped yttrium aluminum perovskite (Tm:YAP) laser rod pumped at 1 064 nm. The results showed that the measured overall efficiency of produced laser at ~1.98 µm is enhanced from 3.9% to 6.9% when the pump spot diameter is reduced from 390 µm to 210 µm. The maximum output power and oscillation threshold are also enhanced with reduced pump spot size. The maximum thermal stress and focal length of thermally induced lens are also addressed.     

Theory of the frequency comb output from a femtosecond fiber laser

The output of a femtosecond fiber laser will form a frequency comb that can be phase-locked through feedback to the cavity length and pump power. A perturbative theory is developed to describe this frequency comb output, in particular for a solitonic fiber laser. The effects of resonant dispersion, saturation of the self-amplitude modulation, cavity loss, third-order dispersion, Raman scattering, self-phase modulation, and self-steepening on the spacing and offset of the fiber-laser frequency comb are given. The mechanisms by which the pump power, cavity length and cavity loss control the frequency comb spacing and offset are identified. Transfer functions are derived for the comb response to change in cavity length, pump power or cavity loss. This theory can potentially be applied to other frequency comb sources as well.     

泵腔结构参数对压电气泵性能影响

为了探究泵腔结构参数对压电气体隔膜泵性能的影响,该文设计了一种压电气体隔膜泵的泵腔结构。首先简述了泵腔的结构设计与工作原理,推导出泵腔出口气流速度的表达式,通过仿真得出泵腔高度、气孔直径对腔体内的瞬时气压、气流速度及气体流量的影响。最后制作了泵腔样机并应用在压电气体隔膜泵中,进行了实验测试及理论分析对比。结果表明,实验结果与理论分析相吻合,输出流量随着腔高的增大而减小,随着气孔直径的增大而增大,这为压电气体微泵的腔体设计提供了理论参考。     

固体激光器腔型结构对热透镜焦距测量的影响

热透镜效应对固体激光器的性能影响很大,准确测量热透镜焦距对固体激光系统的设计有重要意义。考虑热致双折射效应,利用等效谐振腔的g参数坐标图进行分析,推导了三种不同腔型结构下径向热透镜焦距和切向热透镜焦距系数的计算方法,分析并得出了测量热透镜焦距系数所需的腔型结构。实验采用Nd∶YAG作为激光晶体,三组激光二极管互呈120°侧向抽运。实验结果表明,在非对称平-平腔中,当激光晶体相对于两面腔镜位置不同时,谐振腔输出功率会出现不同的变化趋势,测量出径向热透镜系数为31.76 m.W和切向热透镜系数为42.26 m.W。实验验证了理论分析的正确性。     

KTP光学参量振荡器输出激光的空间模式和光束质量

理论上通过二维傅里叶变换求解耦合波方程 ,分析了KTP光学参量振荡器 (OPO)信号光的空间分布 ;实验上利用Nd∶YAG倍频激光 ( 5 3 2nm)抽运非临界 (θ =90°,φ=0°) 及临界相位匹配KTP (θ =62 7°,φ=0°) OPO ,测量了参量光的空间分布、远场发散角及M2 因子等参数 ,讨论了抽运功率、谐振腔长、残余光后向二次抽运对OPO参量光的发散角和光束质量因子M2 的影响。     

磷酸盐双芯光纤的制作和自锁相激光输出

利用堆积法制作出Nd掺杂的磷酸盐玻璃双芯光纤(TCF)。结合管棒法,设计一种能够任意调节芯径与芯间距比例的制备方法。激光实验采用808 nm激光二极管(LD)作为抽运源,以长为6 cm,外径为620 μm的TCF作为增益介质,宽带高反双色镜和TCF另一端的菲涅耳反射形成的F-P腔作为激光谐振腔。抽运功率大于阈值时,CCD观察到清晰的远场干涉条纹,表明得到自锁相激光输出。激光最大输出功率达到52 mW,对应斜率效率为27.1%,并研究了不同抽运功率时,TCF激光的光谱性能。