不锈钢的激光着色研究

已知不同的激光参数组合可在不锈钢表面产生同种颜色，为探究参数和颜色之间的确定性关系，选用波长为1064 nm、最大输出功率为20 W的主控振荡器功率放大器（MOPA）光纤激光器进行实验研究，通过分光光度计对彩色样品的色彩、可见光谱进行采集分析，利用扫描电子显微镜对彩色样品的氧化膜厚度和表面形貌进行测量。结果表明，激光扫描速度、激光重复频率和激光功率按比例同时改变，可在不锈钢表面产生极其相似的色彩和氧化膜。该研究对激光彩色打标的实际应用具有较大的指导意义。     

912nm/1064nm同步双波长激光特性研究

为了研究同步双波长激光器的输出特性,并解决其增益竞争问题,本文介绍了能同时输出准三能级激光和四能级激光的双波长激光器的理论模型,推导了双波长激光器输出功率的表达式.以理论模型为基础,首次设计了一种使用Nd:GdVO4和Nd:YVO4晶体为增益介质,879 nm激光二极管为泵浦源的腔内级联泵浦结构的同步双波长连续激光器,...     

多波长掺铒光纤激光器的研究进展

概述了用于密集波分复用通信的多波长掺铒光纤激光器(MW-EDFL)的研究进展，介绍了实现多波长激光输出的多种方法，并对其原理、实验装置和研究结果进行了详细阐述和分析，展望了多波长激光器的发展方向．     

气溶胶单粒子的检测效率与基质辅助激光解吸电离研究

利用基质辅助激光解吸电离(MALDI)技术,在自行研制的气溶胶飞行时间质谱仪(ATOFMS)上实时探测单个生物气溶胶粒子的粒径和化学成分。采用双束激光空气动力学方法进行气溶胶粒子粒径的测量,并用266 nm的Nd∶YAG激光器对粒子进行激光解吸电离。以2,5-二羟基苯甲酸(DHB)和芥子酸为基质,对多肽生物样品进行了实验研究。质谱峰中质子化的分析物阳离子是在气相时,和基质通过质子转移反应形成的;而分析物碱金属加和物阳离子是在气相离子分子反应中,通过气相阳离子转移反应形成的。气溶胶粒子的检测效率为0.01%左右,命中率为10%左右。实验结果表明,该仪器可以满足大气中气溶胶单粒子的实时在线检测。     

一种新型激光驱鸟器的研究

本文根据高亮度激光束与飞鸟眼睛的相互作用机理，试验研究了激光波长及激光对鸟眼刺激强度之间的关系以及激光驱鸟的有效性，比较各种激光器找出了一种最佳驱鸟的激光器和激光波长。研制了一种适用性强的可以应用在机场区域而且对飞行没有危害的激光驱鸟器。     

在Na-Ne放电管中的光电流光谱学实验

光电流光谱学的原理基于激光感生电流效应.即它是在低压气体或各种金属蒸气中维持恒定的直流放电或脉冲放电的条件下,用可调谐激光器激发放电样品,当激光波长调谐到与放电样品的原子(或分子)跃迁频率时,放电样品的阻抗就发生变化,使回路电流发生相应的变化.用锁相放大器或灵敏示波器对这种变化的信号进行测量.本实验装置由氮分子激光器泵浦的可调谐染料激光器激发样品,波长由光谱仪标定.图1为实验装置示意图.染料激光器采用20倍的扩孔望远镜和每毫米1200条刻线的光栅进行波长调谐,染料用若丹明6G并溶于乙醇中.激光调谐范围从5800     

半导体激光器温度调谐波长扫描技术

低成本、小型化的波长扫描半导体激光器在光纤传感系统中有着重要作用。设计了一种可进行温度调谐的半导体激光光源驱动电路。该电路系统以ARM单片机作为控制中心,利用热敏电阻采样激光工作温度,并通过半导体制冷器(TEC)进行温度调节,使得激光器能够根据温度调谐实现波长扫描；同时通过背向光探测器(PD)采样激光输出功率,并通过改变半导体激光驱动电流实现对激光输出功率的控制,使得激光器在温度变化时输出光功率保持稳定。实验结果表明,该电路能够长时间可靠地工作,激光器能够实现的最大波长调谐范围为5nm,且输出光功率在整个波长扫描过程中保持稳定。     

简明消息

美陆军资助染料激光器研究美陆军导弹指挥研究开发工程中心给物理科学公司（PSI）一份160万美元的合同，继续开发可调谐固态染料激光器。公司激光技术组HenryAldag说“对染料激光器有兴趣是由于它们简单，且波长多样。”但是由于液体介质使用不便，且维修费用高，企业对使用此类激光器仍犹豫不定。公司将研究固态替代品．旨在弄清染料／基质相互作用的光物理学并确定对于不同应用的最佳激光配置。固态基质适宜于在任一可见光谱区产生激光的简单、轻型、价廉的器件。Aldag说：“你基本上在购买一片可处理的塑料片。”Aldag说，“可选择从…     

激光表面清洁的实验研究

激光清洁法较之其它方法有其独特的优点，本文采用ＹＡＧ脉冲激光器作光源，对几类表面附着物的清洁进行了实验研究。初步的实验结果表明，清洁效果令人满意。除材料本身性质外，选择适合的表面清洁的重要参数（激光波长和脉冲宽度）可以提高表面附着物的清洁效率并可降低激光对表面基质材料的危害，本文还讨论了与激光清洁过程有关的其它因素和解决方法。     

新产品介绍——多波长He一Ne激光器

我们向大家推荐一种激光器新产品-“多波长He-Ne激光器”。当这种He一Ne激光器运转时，通过旋转调节机构，改变其入射角，可分别输出四种激光彼长:632.5、611.9、594.1、543.5nm，即可分别输出红、橙、黄、绿色的四种可见光波长的激光。故称这种激光器为“多波长He-Ne激光器”，亦叫“波长可调的He-Ne激光器”。该种激光器的有关结构和主要参数如下:     

Laser post-ionization improves surface analysis

Laser post-ionization (PI), a technique that overcomes the greatest handicap of secondary-ion mass spectroscopy (SIMS), namely, its susceptibility to matrix effects is discussed. The SIMS matrix effect is the often unknown relationship between the chemical composition of a solid and the secondary ion yield of an analyte in the sample, which is unpredictable and can vary as much as seven orders of magnitude. PI, which involves passing a laser beam parallel to, and just above, a surface undergoing stimulated desorption, solves the problem by decoupling the ionization and desorption steps. This allows the detection of secondary neutral species, which typically constitute more than 95% of the material removed from the surface during ion beam sputtering. This largely eliminates matrix effects because the chemical matrix generally has much less influence on the emission of charged particles. To compete with SIMS on sensitivity, PI methods efficiently ionize sputtered neutrals and detect those positionized particles. The nonresonant method of PI, which comes in two variations, nonresonant multiphoton and nonresonant single-photon ionization and is called SALI (surface analysis by laser ionization), is described, and its application to semiconductors is examined     

Laser-Induced Surface Reconstruction of Nanoporous Au-Modified TiO2 Nanowires for In Situ Performance Enhancement in Desorption and Ionization Mass Spectrometry

The physicochemical properties of nanostructured substrates significantly impact laser desorption/ionization mass spectrometry (LDI-MS) performance. Fundamental understanding of the substrate properties can provide insights into the design and development of an efficient LDI matrix. Herein, a hybrid matrix of nanoporous Au-modified TiO₂ nanowires (npAu-TNW) is developed to achieve enhanced LDI-MS performance. Its origin is investigated based on hybrid matrix properties including photo–thermal conversion and electronic band structure. Notably, further improvement is obtained in the npAu-TNW than in the pristine TNW and non-porous Au nanoisland-modified TNW (Au-TNW) hybrid, which is attributed to the laser-induced surface restructuring/melting phenomenon. Noticeable surface restructuring/melting occurs in the npAu by laser exposure through efficient photo–thermal conversion of the highly porous npAu. At this instant of npAu structural changes, internal energy transfer from the npAu to the adsorbed analyte is promoted, which facilitates desorption. Moreover, strain is developed in situ in the TNW adjacent to the restructuring npAu, which distorts the TNW lattice. The strain development reduces recombination rates of charge carriers by introducing shallow trap levels in the bandgap, which enhances the ionization process. Ultimately, the high LDI-MS performance based on the npAu-TNW hybrid matrix is demonstrated by analyzing neurotransmitter.     

激光解吸电离飞行时间质谱计的谱峰定标

研制了一套飞行时间质谱计（TOF）,能够同时或分别在电子碰撞电离（EBI）和激光解吸电离（LDI）两种机制下工作。利用EBI模式下得到的真空残气质谱图,对LDI模式下得到的TOF质谱峰进行了定标。通过在作为LDI靶材的金属基底表面添加碱金属卤化物的实验,证实了这种定标方法的可行性。     

细胞色素C的基体辅助激光脱附／电离质谱研究

采用基体辅助激光脱附和电离法，分别以肉桂酸和２；５－二羟基苯甲酸作为基体，在飞行时间质谱中测得细胞色素Ｃ的相对分子质量为１２７８０ｕ；并观察到它的多聚体离子。实验结果表明，肉桂酸是比较理想的基体，同时还考察了Ｎａ＋离子存在对测定结果的影响。     

CCl_4在低温表面上的紫外激光脱附

本文研究了ＣＣｌ４低温（１３０Ｋ）吸附于石英表面上经紫外激光辐照后引起的脱附过程。由时间分辨四极质谱测得脱附产物的飞行时间谱表明，在高激光能量密度下，表面上吸附厚层的ＣＣｌ４分子发生爆炸脱附，超热的ＣＣｌ４分子最高动能可达３．５ｅＶ。     

大气气溶胶质谱研究进展

文中较为详细地介绍了大气气溶胶粒子质谱研究的发展概况，从离线的质谱测量技术到实时在线的测量技术，特别是目前应用较为广泛的激光电离气溶胶飞行时间质谱技术——一种可以同时测量气溶胶粒子的大小和化学成分的方法的原理和应用。     

Trace Analysis and Reaction Monitoring by Nanophotonic Ionization Mass Spectrometry from Elevated Bowtie and Silicon Nanopost Arrays

Silicon nanopost arrays (NAPA) are used in trace analysis by mass spectrometry (MS) because they enable highly efficient ion production from small molecules and thin tissue sections by UV laser desorption ionization (LDI). Such nanophotonic ionization of adsorbates relies on localized interactions between a nanostructured substrate and laser radiation. In LDI from NAPA, only the component of the oscillating electric field vector that is parallel with the posts couples the laser energy into the nanostructure. Enhancements in control over adsorbate ionization and fragmentation are expected if the surface‐parallel component can also interact with the nanostructure. Here, an alternative nanophotonic ionization platform is introduced for LDI‐MS, the elevated bowtie (EBT) array by adding triangular chromium features on top of silicon post pairs to form bowties. Compared to NAPA, the threshold fluence for ionization from EBT is lower, and at low laser fluences the ionization efficiency is increased by a factor of ≈17. The EBT platform with optimized apex angle exhibits a higher survival yield for molecular ions produced from biomolecules and xenobiotics and allows more control over fragmentation by adjusting the fluence. These unique nanophotonic ionization attributes are utilized for trace analysis and reaction monitoring in complex biological samples.     

Chemical degradation processes of highly stable red phosphorescent organic light emitting diodes

We investigate the chemical degradation processes of highly stable red organic light emitting diodes (OLEDs) based on the triplet emitter tris(1-phenylisoquinoline)iridium(III) by laser desorption/ionization time-of-flight mass spectrometry (LDI-TOF-MS). The analysis of LDI-TOF spectra, collected on OLEDs driven at different current densities, shows a direct correlation between the lifetime of the devices and the formation of the three different reaction products: a BPhen dimer, an adduct of BPhen dimer with cesium, and the complex [BAlq₂ + Al(Me-q)₂]⁺ as well. Additionally it was possible to identify another degradation product, whose chemical structure is related to the α-NPD molecule as well to the fluorine of the used p-dopant. This product is only observable in devices aged at very high current densities.     

Wafer thermal desorption spectrometry in a rapid thermal processorusing atmospheric pressure ionization mass spectrometry

This paper demonstrates the possibility of performing thermal desorption spectrometry (TDS) on wafers in an atmospheric pressure rapid thermal processor (RTP). A special gas sampling system is described, which allows the analysis of gas composition inside the RTP chamber with atmospheric pressure ionization mass spectrometry (APIMS). Sampling is controlled with no valve operation and high dilution of the sample gas flow can be achieved while maintaining a short sample transfer time. It is shown how gas flows can be optimized to improve the sensitivity and resolution of TDS spectra. The RTP-APIMS setup was used in a study of H ₂O absorption by low dielectric constant fluorinated silica glass (FSG) films, helping to develop a cap that reduced H₂O absorption upon storage by a factor of 60. NH₃ is shown to desorb from FSG and SiO₂ films deposited by plasma-enhanced chemical vapor deposition (PECVD), which may be of concern for the reliability of integrated circuits