大功率脉冲氙灯紫外光谱及色温

用作Nd~(+3)玻璃激光器泵浦光源的大功率脉冲氙灯的辐射光谱,对于激光器设计是一个重要的物理参数。对Nd~(+3)玻璃大功率激光器来说,有用的主要在可见和近红外的几个吸收峰。其紫外强辐射对激光器则是不利的,它会导致聚光腔内的光感生冲击波,降低了器件稳定性。严重时会引起激光器元件破坏,同时引起工作物质产生色心等。为了抑制氙灯的紫外辐射,大功率激光器系统采用滤除紫外的掺铈石英管制作氙灯。对这种掺铈石英管氙灯的光谱能量分布,过去我们已经测试了从406～1000nm     

掺铈石英玻璃管低重复率脉冲氙灯的研制

低重复率脉冲氙灯作 Nd∶YAG 的泵浦源时,由于重复率低 f=0.5—1次/秒,灯的电极溅射严重,光效下降很快,而且普通石英灯管由于铝、锂等杂质的影响,在氙灯紫外辐照下,容易产生“色心”。这些都是造成该种氙灯寿命低的原因,也是付诸实用的重要障碍.我们研制成功的掺铈石英玻璃管低重复率脉冲氙灯(内径8mm,长80mm),在输入能量为50～80焦耳时,寿命达百万次以上。该灯使用在 Nd∶YAG 倍频激光器中,使器件长期工作的稳定性、可靠性均达到较高水平.且由于不再需要重铬酸钾滤光液,给使用者带来了便利,延长了器件寿命及提高了总体效率。     

OMA-2快速测定微秒级脉冲灯的光谱分布和光谱效率

采用OMA-2系统,测定了脉宽为3微秒的脉冲氙灯在2200～8800(?)波段的光谱分布和光谱效率。 研究了不同放电电压、不同充气压力对脉冲灯光谱输出的影响。结果表明,随放电电压和充氙压力的增加,脉冲氙灯的紫外光谱效率从13％增加到17％左右,紫外总辐射能量也显著提高。     

大功率脉冲氙灯灯管透过率的研究

大功率脉冲氙灯是惯性约束聚变(ICF)装置的核心器件,它的光效直接影响ICF的输出效率,氙灯灯管的透过率是氙灯光效下降的重要原因。在大功率脉冲氙灯运行不同发次后,复合石英灯管透过率会下降。实验选取了脉冲氙灯放电0发次、88发次、2000发次、3000发次、5000发次、8000发次后的复合石英管中部,对这些样品进行光谱透过率测试并加以对比,发现灯管的透过率在88发次到8000发次就趋于稳定,不再明显下降。为找到复合石英灯管透过率下降的原因,特选取放电试验0发次和2000发次的复合石英灯管(灯管中部和靠近阴极部分),进行透过率、X射线衍射、荧光、成分分析测试,分析其中原因:氙灯在运行过程中,复合石英灯管内没有晶体析出,说明透过率下降并不是由于析晶导致的;灯管掺铈层铈离子价态的转变可能是透过率下降的一个原因;电极溅射出较多杂质附着在灯管内壁上,则是导致靠近电极附近灯管透过率下降的另一个原因。     

细长型高功率脉冲氙灯

高功率脉冲氙灯主要在惯性约束聚变(ICF)研究中用作高功率激光驱动器的抽运光源,其各项性能和使用寿命对高功率激光驱动器的整体工作性能影响很大。在改进制灯材料和管壁结构的基础上,研制了两种不同规格的细长型高功率脉冲氙灯:一种是in16 mm,放电弧长为1140 mm;另一种是in17 mm,放电弧长为1270 mm。研制的细长型高功率脉冲氙灯,其极限负载能量大、工作寿命长、辐射效率高,工作性能较原先脉冲氙灯有很大的改进和提高。     

1411所研制成无紫外长寿命脉冲氙灯

1411所与建材院多年协作,在管壁掺铈脉冲氙灯研制成功的基础上,近期又研制出无紫外、长寿命脉冲氙灯。此种灯的寿命在额定能量下可达一千万次以上。它可在无任何滤紫外光的措施下泵浦Nd:YAG。因此这种灯必将对     

掺杂石英玻璃管脉冲氙灯及滤光套管在激光器中的应用

采用合适厚度,掺杂合适浓度的铈、铕等稀土元素的石英玻璃管制作的脉冲氙灯和滤光套管,其3500埃以下的紫外辐射基本消除,因而在固体激光器中能替代滤光溶液和黄色玻璃滤光套管,防止工作物质着色.比较了不同滤光材料的滤光特性及其在重复频率钇铝石榴石激光器中的激光效率.在Nd:YAG及钕玻璃激光器中,使用掺杂石英玻璃后,可使激光器效率提高25～100%.     

利用紫外激光处理提高熔石英损伤阈值的研究

为了研究紫外脉冲激光预处理对熔石英表面形貌的影响,验证其对熔石英元件抗紫外激光损伤能力的提升效果,利用输出355nm 3倍频紫外脉冲激光的YAG激光器,采用光栅式扫描的方式对熔石英表面进行了全口径能量周期递增的激光预辐照处理,并在处理结束后研究了表面形貌的变化,考核了其在355nm脉冲激光作用下的损伤阈值.结果发现,石英基片在经过紫外脉冲激光预处理后表面杂质得到有效清除并暴露了低阈值缺陷,处理后的石英基片零几率损伤阈值平均提高24%左右,50%损伤阈值提高约19%.结果表明,紫外激光预处理是增强熔石英元件紫外激光负载能力的有效方法,可有效缓解高功率固体激光装置3倍频输出的负载瓶颈,具备较高的工程运用价值.     

利用紫外激光处理提高熔石英损伤阈值的研究

为了研究紫外脉冲激光预处理对熔石英表面形貌的影响,验证其对熔石英元件抗紫外激光损伤能力的提升效果,利用输出355nm3倍频紫外脉冲激光的YAG激光器,采用光栅式扫描的方式对熔石英表面进行了全口径能量周期递增的激光预辐照处理,并在处理结束后研究了表面形貌的变化,考核了其在355nm脉冲激光作用下的损伤阂值。结果发现,石英基片在经过紫外脉冲激光预处理后表面杂质得到有效清除并暴露了低阈值缺陷,处理后的石英基片零几率损伤阈值平均提高24%左右,50%损伤阈值提高约19%。结果表明,紫外激光预处理是增强熔石英元件紫外激光负载能力的有效方法,可有效缓解高功率固体激光装置3倍频输出的负载瓶颈,具备较高的工程运用价值。     

光伏电池组件太阳模拟器AM1.5滤光片的研究

通过将标准大气光谱与大功率圆弧形氙灯光谱的比较,获得了AM1.5型太阳能模拟器滤光片的透射率光谱曲线。通过膜系设计和镀制,研制出了中心波长为930 nm的负滤光片,该滤光片在930 nm处的透射率T=15%,400～750 nm波段内的平均透射率Ta≥93%,1200～1400 nm内平均透射率Ta≥91%。将6片相同的滤光片安装在测试面为1 200 mm×2 000 mm的脉冲式光伏组件太阳模拟器上进行测试,在氙灯的正上方,其光谱匹配度在0.91~1.05之间,达到了A类滤光片要求;而在离圆弧氙灯最远的位置2处,测试的光谱匹配度在0.73~1.06之间,达不到A类滤光片要求。最后,通过采用滤光片的优化组合拼接技术,使光伏电池组件模拟器测试面上所有点的光谱匹配度均达到了A类要求。     

The correlation between the static stress distribution and the explosion energy of fused-quartz flashlamps

Experimental data are presented which indicate that the explosion energy of fused-quartz flashlamps is significantly higher for those lamps which have predominately compressive stresses at the surface of the lamp envelope. Techniques for increasing the mechanical strength of a flashlamp are suggested.     

过渡玻璃封接的大口径脉冲氙灯研究

报道一种过渡玻璃封接的大口径脉冲氙灯,其密封性能好,极限负载大,基本输出特性与过渡玻璃封接的小口径脉冲氙灯基本相同。主要在ICF研究中用作大功率激光器的泵浦光源。     

碱金属泵浦灯的实验研究

实验研究了多晶氧化铝管钾-汞灯、钾-铷灯在重复频率运转条件下泵浦Nd~(3+):YAG的激光特性.与同类型氙灯进行了比较,在一定功率范围内.钾-汞灯的激光泵浦效率比氙灯高60%.探讨了碱金属蒸气灯中若干特有的工艺问题,对碱金属灯的进一步工作提出了设想.     

Rare-Gas pumping efficiencies for neodymium lasers

A comparison of rare-gas flashlamps for pumping YAG: Nd³⁺and neodymium-doped glass, which shows krypton lamps to be superior to xenon under certain circumstances, is presented. The emission spectra of argon have the best match to the neodymium absorption spectra, but argon lamps suffer from low radiative efficiency except at very high pressures. A detailed analysis of theoretical laser thresholds, which takes into account pump-pulse duration, cavity transfer coefficient, laser rod diameter, lamp emission spectra, and other pertinent parameters, is compared to experimental threshold data with good agreement. Krypton at 500-mm pressure gives a 19-percent improvement in the YAG : Nd³⁺threshold over a comparable xenon lamp at low current densities. Xenon is generally superior to krypton for pumping glass rods because of the greater absorption at 5900 Å where xenon is intrinsically a better radiator. However, proper lamp optimization shows a definite improvement in threshold with krypton at low drive levels. Xenon is anticipated to be superior to krypton at high current densities since line radiation will no longer contribute significantly to the pumping process. Proper optimization of lamp and cavity parameters should permit a slope efficiency of ∼6 percent for neodymium lasers to be realized.     

A comparison of rare-gas flashlamps

Spectral data for argon, krypton, xenon, and neon flashlamps are presented for the region of lamp operation in which the line radiation makes up a substantial portion of the total radiant energy. The spectral charateristics are presented in terms of both power flux and emitted quanta per unit area per second, the latter being appropriate for the characterization of illumination and laser pumping efficiencies. The emission spectra show strong line radiation peculiar to each gas superimposed on a low emissivity background continuum. The electrical resistance coefficientk (in Omega.A^{1/2})is presented for each gas and is shown to increase with increasing gas atomic weight and pressure. An analysis of lamp radiative efficiency indicates that through proper optimization of the gas pressure, the efficiency and overall output of the lighter rare gases will be comparable to those for optimized xenon lamps with optimum pressures increasing with decreasing gas atomic weight. Overall lamp efficiencies are shown to be as high as 40 percent in the0.4-1.1-muregion.     

闪光灯泵浦波导染料激光器的性能研究

在闪光灯泵浦平板自波导染料激光器上,用掠入射光栅调频腔获得了窄线宽的调谐稳定输出.调谐范围460(?),调频效率在85%以上,窄线8GHz(FWHM),孤矢发散角为13mrad.     

High-efficiency cathode-ray tubes for dry-process recording

Typically, dry-process-recording media is sensitive only in the ultraviolet (UV) region of the spectrum, where current phosphors and faceplate glasses are either inadequate or unavailable. Thus, it was considered necessary to develop new phosphors and fiber-optic faceplates for incorporation in high-resolution cathode-ray tubes (CRTs) to be used for these dry-process real-time-recording applications. Two rugged UV phosphors, which emit radiation centered near 320 nm and 380 nm, are joined with newly developed fiber-optic faceplates to produce CRTs that may be used to write on almost any of the mentioned recording media. Up to tenfold improvement in writing speed on appropriate media is shown to be possible.     

Xenon flashlamp triggering for laser applications

Results of an investigation into the triggering of linear xenon flashlamps are presented, with particular reference to xenon flashlamps in laser applications. Measurements are described which give information on the arc formation process, trigger voltage thresholds, peak trigger currents, lamp energy output stability, and electromagnetic interference (EMI) for both series and parallel triggering. Particular attention is given to the performance obtained with both the correct and the incorrect polarities for the two types of triggering. The investigation makes extensive use of a high-speed streak camera and a wideband (100 MHz) continuous sweep spectrum analyzer, as well as more conventional instrumentation. It was found that: 1) the triggering process is extremely fast (≤50 ns) for both methods, but that parallel triggering produces trigger currents which are 100 times smaller than series; 2) the trigger current rather than the main energy, discharge current is the dominant EMI source; 3) the measured RF spectra show the corresponding EMI superiority of parallel over series; and 4) the two methods are equivalent in regard to the effect on lamp efficiency and stability.