具有最大输出功率的CO2激光器谐振腔

提出了一种优化设计激光器谐振腔参数的新方法。应用遗传算法,以最大输出激光功率为目标函数,对典型CO2激光器谐振腔和放电管参数进行了优化,给出了谐振腔的3个优化参数:放电管直径、谐振腔凹面反射镜曲率半径和出射镜透射率。对于1.2m长谐振腔,优化设计的基模激光功率可从原先的55W提高到89W,实际测量提高到74W。     

基于孤子自压缩的高功率少周期2 μm激光产生（特邀）

具有少周期量级脉冲宽度的高功率2 μm波段超快激光在非线性频率变换、激光光谱学以及医疗等领域有着重要且广泛的应用。利用高功率2 μm超快光源驱动孤子自压缩是产生高功率少周期2 μm激光的一种有效方法。文中利用自建的2 μm Ho:YAG锁模碟片振荡器作为种子源,在大模场光子晶体光纤中进行光谱展宽并实现孤子自压缩,最终获得了平均功率为10.2 W、脉冲宽度为3个光学周期的2 μm激光输出。实验采用FROG对输出脉冲的宽度和光谱进行测量,并与波长计测量的光谱以及理论模拟的结果进行了比较,验证了实验结果的准确性。     

CO/sub 2/ laser processing of alumina (Al/sub 2/O/sub 3/) printed circuit board substrates

We report the results of an investigation of the laser-material interaction processes involved in laser drilling of alumina, through the use of an enhanced peak power (2.5 kW) CO/sub 2/ laser and novel temporal pulse formats. Peak power was varied from 30 W to 2 kW for pulses of constant energy to observe the effect produced on scribe depth. High-speed videography of hole formation has been combined with microscopic analysis to investigate the key processes involved in laser processing of alumina. Plasma screening was observed for short, high peak power laser pulses, and optimal scribing was achieved in the weakly plasma absorbing regime. A new processing technique for scribing alumina has been developed, which exploits the fast response of the laser to produce novel temporal pulse shapes, which can be modified to generate cleaner holes. Scribe speeds of up to 280 mm/spl middot/s/sup -1/ were obtained for scribe holes >200 /spl mu/m deep and 150 /spl mu/m apart, with no material plugging the hole, in 0.635-mm-thick 96% alumina.     

内腔倍频被动调QNd∶YVO_4/KTP激光特性的研究

实现了激光二极管(LD)抽运Nd∶YVO4/KTP,GaAs饱和吸收体被动调Q绿激光运转。测量了GaAs不同 厚度情况下的脉冲重复率、脉冲宽度、单脉冲能量及峰值功率随抽运功率的变化关系。在抽运功率3.22W下,300 μm厚的GaAs获得了381kHz的高重复率,53.2ns的脉冲宽度,0.18μJ的单脉冲能量。通过求解内腔倍频GaAs 调Q工作原理的耦合波方程组,所得的理论值与实验结果相符。     

复合热像法定量测量红外激光辐照度分布

为解决红外摄像法测量激光辐照度分布难以定量的问题,结合红外摄像法和量热法,提出了复合热像法的测量方案,研制了一套激光辐照度时空分布测量原理性样机,测量了2 000 W级Nd:YAG激光的辐照度分布。结果表明：利用漫反射屏上安置少量量热式激光能量探头的方式可以实现基于红外摄像法的绝对定标测量,通过红外漫反射数据与能量探头数据的归一化处理,可以得出红外激光辐照度的时空分布的定量结果。该样机系统为国内首创,并成功应用于红外强激光的辐照度定量测量。     

Picosecond laser diode pulse amplification up to 12 W by laserdiode pumped erbium-doped fiber

Intense picosecond optical pulse generation from a gain-switched laser diode (LD) was demonstrated using a 1.48-μm LD-pumped Er³⁺ -doped fiber laser amplifier. Saturation characteristics of the amplifier output power were also measured as a function of input repetition frequency. An amplified peak power of 12 W and 105-pJ pulse energy were obtained for 9-ps pulses at a 33-GHz repetition frequency. This is the highest peak power yet demonstrated in pulse generation employing all-laser diodes as active devices     

激光雷达用高性能光纤激光器

系统研究了窄线宽低噪声单频连续光纤激光器、高能量纳秒长脉冲单频光纤激光器以及高峰值功率纳秒短脉冲光纤激光器三类高性能光纤激光器:实现了工作于1、1.5及2 m波段的单频连续光纤激光器,典型光谱线宽小于3 kHz,强度噪声接近于散粒噪声极限;实现了高能量单频光纤激光器,脉冲能量超过200 J,重复频率20 kHz,脉冲宽度100~500 ns,激光波长位于1.5 m波段;实现了高峰值功率纳秒短脉冲光纤激光器,峰值功率超过700 kW,重复频率10 kHz,脉冲宽度3 ns;同时还实现了高重频高峰值功率纳秒短脉冲光纤激光器,峰值功率超过200 W,重复频率3 MHz,脉冲宽度1~5 ns。文中阐述了以上几类高性能光纤激光器在激光雷达探测系统中的应用前景。     

声光调制CO_2激光放大器

本文叙述了CO_2激光的布喇格衍射型声光调制及放大装置。放大器输出已调制的10.6μm激光115w,最大调制频率200kHz。激光放大器的放大指数随输入功率上升而减小。     

波导CO2激光与CO2激光治疗面部色素痣疗效的比较

面部色素痣很常见,大小及数目不定,有的扁平成斑,有的隆起成丘疹或结节状,有毛或无毛,呈灰黄、灰褐或黑色,常影响面容,少数可发生恶变。冷冻及腐蚀药物往往不能完全消除痣细胞。我们从1977年11月至1982年 1月用30～40WCO_2激光器治疗面部色素痣262例,大部分病灶一次清除,但由于功率较大,深浅难以掌握,浅者易复发,深者易留疤痕,影响美容效果。1982年2月至1895年5月改用波导CO_2激光治疗254例,     

Reducing pulse durations in diode pumped Q-switched solid-state lasers

The authors describe a subminiature, laser-diode-pumped, acoustooptic Q-switched Nd:YLF laser. The laser utilizes a very short cavity and laser crystal cooling to increase gain and reduce pulse width. Exploiting this technology results in 1.321 mu m pulses with durations and peak powers of 4.7 ns and 1100 W at 2 kHz and 8.7 ns and 250 W at 10 kHz in Nd:YLF. Similarly, 10 kHz pulses at 1.047 mu m have 2.7 ns duration and 1500 W peak power, also in Nd:YLF.<>     

2 μm波段Tm:YAP晶体半导体可饱和吸收镜连续波锁模激光器

使用半导体可饱和吸收镜,实现了光纤耦合半导体激光抽运Tm:YAP晶体的全固态连续波锁模激光运转。根据ABCD矩阵理论设计激光器参数,通过控制谐振腔的像散和模式分布,获得了稳定的皮秒锁模激光输出。当最大抽运功率为7.96 W时,获得锁模激光的最大平均输出功率为0.73 W,相应的斜效率为15.6%。此时锁模脉冲宽度约为1.7 ps,对应的重复频率为88.7 MHz,中心谱线为1 982.4 nm。结果表明:Tm:YAP晶体是一种具有较好的热学、机械性能的2 m波段超快激光晶体。     

CO2激光治疗尖锐湿疣870例临床总结

目的探讨CO2 激光治疗尖锐湿疣的方法和疗效。方法采用 0～ 5 0W连续可调CO2 激光器 ,波长 1 0 .6 μm ,光斑直径 0 .4～ 0 .9mm ,对 870例尖锐湿疣进行切割 ,气化、凝固 ,并同时配合干扰素治疗 .结果一次性治愈 84 2例 ,占 96 .8% ,二次性治愈 2 0例 ,占 71 .4 %。总治愈率 1 0 0 %。结论CO2 激光配合干扰素治疗尖锐湿疣是有效、安全的治疗方法 ,能有效地减少再发。     

LD抽运高功率连续波1.34 μmNd:GdVO4激光器研究

报道了利用光纤耦合大功率半导体激光器(LD)抽运Nd:GdVO4晶体,采用平凹谐振腔,输出1.34 μm波长的高功率连续波固体激光器.在抽运功率为14.75 W时,获得最大输出功率为4.62 W,光-光转换效率为31.3%,斜率效率达32.9%.利用实验测得的阈值抽运功率和斜率效率,计算了Nd:GdVO4晶体在1.34 μm波长处的受激发射截面.     

Microwave Nanosecond Pulse Burnout Properties of GaAs MESFET's

Microwave nanosecond pulse burnout data have been measured at 9.3 GHz for three commercially available 1-mu m gate MESFET's. Values for the incident pulse power required to cause burnout are concentrated in the ranges 4-10 W for 10-ns pulses, 12-25 W for 3-ns pulses, and 15-30 W for 1.5-ns pulses. The corresponding values for the absorbed microwave pulse energy required to cause burnout are concentrated in the ranges 0.3 to 0.6 ergs for 10-ns pulses, 0.2-0.4 ergs for 3-ns pulses, and 0.2-0.35 ergs for 1.5-ns pulses. Two dominant failure modes in overstresed MESFET's have been observed. One is a gate-to-source low-resistance path (5-25 Omega) which frequently is correlated with metal migration (mainly gold) from the source metallization to the gate metallization. This failure mode was dominant when MESFET's failed at lower power Ievels as at 10 ns. The other dominant failure mode is a reduction in I/sub DSS/ or a drain-to-source short which is correlated with massive damage in the channel region between the source and gate metallizations. This failure mode was dominant when MESFET's failed at high power levels as at 1.5 ns.     

选频~(14)CO_2-~(12)CO_2同位素激光器

我们研制了一台~(14)CO_2-~(12)CO_2同位素激光器,测量到激光谱线80条,其中40条是~(14)CO_200°1-(10°0,02°0)_I带的激光跃迁谱线,强线输出功率达4.0W以上;实验还观察到同位素的竞争效应,发现即使~(14)CO_2成份低于~(12)CO_2,其激光辐射仍占优势.     

新型微波激励汞原子激光器的实验研究

介绍一种新型微波激励的光抽运汞原子激光器。该激光器采用全介质内腔同轴型结构 ,放入微波波导内 ,采用微波激励产生激光。微波波导内注入的微波功率为 80W ,抽运灯吸收功率为 30W左右。激光器腔镜为绿光全反射镜 ,反射率约为 99 9% ,曲率半径为 2m。激光波长 5 46 1nm ,激光器最大输出功率达 0 1mW ,输出光斑为多模结构 ,尺寸约 3mm左右。实验结果表明 ,采用微波激励时 ,这种激光器结构简单紧凑 ,可产生具有良好相干性的激光束。     

不同激光脉冲作用下ZnS晶体非线性光学特性

用Z-scan技术在532 nm的皮秒激光脉冲和800 nm飞秒激光脉冲作用下分别研究了ZnS晶体的非线性吸收及非线性折射特性。实验结果表明,ZnS晶体在532 nm的皮秒激光脉冲作用下非线性吸收为双光子吸收,其非线性吸收系数为5.310-11 m/W,在800 nm的飞秒激光脉冲作用下非线性吸收为三光子吸收,非线性吸收系数为0.5910-21 m2/W2;在532 nm皮秒激光脉冲作用下,ZnS晶体的非线性折射率符号为负,自由载流子产生的非线性折射率的改变占主导,而800 nm飞秒激光脉冲作用下,ZnS晶体的非线性折射率符号为正,束缚电子产生的非线性折射率的改变为主要因素。     

Mode-locked Pr3+-doped silica fiber laser with anexternal cavity

We present a Pr³⁺-doped silica-based fiber laser mode-locked by using a linear external cavity with a vibrating mirror. Stable laser pulses with a FWHM of less than 44 ps, peak power greater than 9 W, and repetition rate up to 100 MHz are obtained. The pulse width versus cavity mismatch ΔL and pump power have been investigated. With a short piece of nonlinear fiber included in the external cavity, laser pulses of 45 ps have been measured     

Ho∶YLF激光泵浦的长波红外ZnGeP2光参量振荡器

以2.05μm Ho∶YLF激光器作为光源,泵浦了长波ZnGeP₂光参量振荡器,实现了高效率、高重复频率的长波激光输出。激光器输出的峰值波长为8.1μm,最大输出功率为3.2 W@10 kHz,泵浦激光到长波激光的光光转换效率为12%,斜效率为19.3%,激光单脉冲宽度为27.11 ns,单脉冲能量为0.32 mJ,单脉冲峰值功率为11.8 kW,X方向的光束质量因子为4.5,Y方向的光束质量因子为4.2。