硫化钠表面增强拉曼光谱及其在味精检测中的应用研究

采用表面增强拉曼光谱(SERS)表征了硫化钠分子的振动模式,获得了硫化钠较为全面的分子结构振动信息,确定以472 cm-1的特征峰为研究对象。以金溶胶为表面增强活性基底,研究了金纳米粒子粒径对增强效果的影响,确定粒径为97 nm的金溶胶增强效果最佳。以硝酸作为促凝剂,测得不同浓度硫化钠溶液的SERS。结果表明,当硫化钠浓度低至10-6 g·mL-1时,依然可以得到明显的拉曼光谱信号,光谱强度与金溶胶和硫化钠溶液的配比有关。将这种硫化钠的检测方法应用于味精样品的检测之中。分别在不同浓度的10 mL硫化钠溶液中溶入1 g味精,检测所得溶液的SERS。结果表明,当每千克味精中硫化钠的含量为10 mg时仍可检测出SERS信号,此种方法无需样品的预处理,操作简便快捷,在味精中硫化钠的定性检测方面具有特有的优势。     

Investigation on the effect of beam divergence angle upon output waveform based on stimulated Brillouin scattering optical limiting

This paper investigates the effect of beam divergence angle on output waveform based on stimulated Brillouin scattering optical limiting. Output waveforms in the case of different pump divergence angles are numerically simulated, and validated in a Nd:YAG seed-injected laser system. The results indicate that a small pump divergence angle can lead to good interaction between pump and Stokes, and a platform can be easily realized in the transmitted waveform. In contrast, a peak followed by the platform appears when the divergence angle becomes large.     

Generation of flat-top waveform in the time domain based on stimulated Brillouin scattering

A method of generating a flat-top waveform in the time domain based on stimulated Brillouin scattering (SBS) is proposed. The transmitted pulses are simulated with pump wavelength at 1064 nm and 532 nm, respectively, and validated in the experiment performed with the Nd:YAG seed-injected laser. The experimental results agree well with the theoretical simulation. With 532 nm pump wavelength, the top of the transmitted pulse is almost a platform, while there is a peak in the front and a platform in the back with 1064 nm pump wavelength. The mechanism behind the generation of flat-top waveform with 532 nm pump wavelength is analyzed in details. PACS 42.65-k; 42.65.Es; 42.65.Hw     

一种利用混合介质测量SBS介质布里渊线宽的方法

提出了一种利用双池受激布里渊散射(SBS)系统选用混合介质,进而测量SBS介质布里渊线宽的方法.在紧凑双池SBS系统的放大池中放入待测介质,在振荡池中放入布里渊频移可调的混合介质,测出放大池待测介质增益系数随布里渊频移偏离的洛伦兹曲线,该曲线半高处的线宽即为待测介质的布里渊线宽.实验上在Nd:YAG调Q激光系统中,选用CCl₄/C₆H₆混合介质,测量了四氯乙烯(C₂Cl₄)、六氯丁二烯(C_{关键词： 受激布里渊散射 混合介质 布里渊线宽}     

船用烟火信号光强测试技术研究

救生信号弹是民用船只海上救生的必要设备,其质量的好坏直接关系到人身安全。根据照度距离平方反比定律,结合光电技术和计算机辅助技术,研究救生信号弹的信号光强测试,构建测试系统。通过编写的测试软件,将测得的信号直接输入计算机,并直观地显示结果。实现了简易、快速测量救生信号弹发光强度和遮光率的目的。实验证明：该系统稳定可靠,并且符合生产企业生产过程在线检测的需要。     

关于有界对称域上的混合范数空间

本文研究了Ｃｎ中有界对称域Ω上的混合范数空间Ｈ（ｐ，ｑ，　）其中０＜ ｐ＜　，０＜ｑ＜　，　是正规函数，给出了Ω上全纯函数ｆ的分数导数ｆ［β］和 分数积分ｆ［β］属于（ｐ，ｑ，）的等价条件。应用这些结果，就两种情形０＜ｐ≤２， ０＜ｑ＜　和２≤ｐ＜，０＜ｑ＜ ，用全纯函数ｆ的展式中的系数，分别给出了 ｆ　Ｈ（ｐ，ｑ，）的必要条件和充分条件，并证明了多调和函数ｕ组成的混合范数空 间ｈ（ｐ，ｑ，）（０＜ｐ，ｑ＜　）是自共轭的．     

Spectrum evolutions of spontaneous and pump-depleted stimulated Brillouin scatterings in liquid media

A theoretical model for calculating spontaneous and stimulated Brillouin scattering(SBS) spectra is described. An empirical formula for the Stokes output spectral linewidth, a function of spontaneous Brillouin linewidth and the exponential gain coefficient, is obtained by the calculated data fitting. The formula holds true for two cases involving pump undepletion and depletion. The lineshape change from spontaneous to highly pump-depleted SBS spectra is also investigated. The result shows that for the pump power below the SBS threshold, the Stokes output spectral lineshape evolves from Lorentzian to approximately Gaussian as the pump power increases. For the pump power near or beyond the threshold, the SBS spectrum is in the form of a steady Gaussian profile, and the spectral linewidth comes to a certain value about 7 times narrower than the spontaneous one. The theoretical results are experimentally demonstrated by using several common liquid media.     

选用新介质的双池受激布里渊散射系统的研究

从介质化学结构与吸收系数的关系入手，寻找出系列吸收系数小，适合作为放大池介质的新介质，例如四氯乙烯(C₂Cl₄)，1，3-六氯丁二烯(C₄Cl₆)和六氟化苯(C₆F₆)等，并计算或测量了入射光波长为1.064μm时的新介质受激布里渊散射(SBS)参数.在双池SBS系统的放大池中分别选用C₂Cl₄和C₄Cl₆，振荡池中均选用光学击穿阈值高，并且布里渊频移与C₂Cl₄和C₄Cl₆的布里渊频移非常接近的乙醇(C₂H₅OH)，并利用Nd:YAG调Q激光器研究了该系统的性能.实验结果表明，该系统具有高负载能力，高相位共轭保真度和高能量反射率稳定度等性能. 关键词： 受激布里渊散射 双池SBS系统 新介质     

Measurement of intrinsic Brillouin linewidth of fibers based on stimulated Brillouin scattering slow light

Intrinsic Brillouin linewidth is one of the essential parameters to optimize the gain spectrum of stimulated Brillouin scattering (SBS). A novel method for the measurement of the intrinsic Brillouin line-width based on SBS slow light is proposed and demonstrated. In this method, an implicit model based on the transient SBS theory is developed, and a data processing method is designed to obtain the value of the intrinsic Brillouin linewidth from the model. The measured results show that the method is effective for studying SBS slow light.     

利用受激布里渊散射能量反射率测量液体介质运动黏度方法的研究

本文提出了一种利用受激布里渊散射(SBS)能量反射率的变化测定不同温度时的液体介质运动黏度的方法.液体介质的运动黏度随温度而变化,这导致了介质增益系数和SBS能量反射率的变化,因此通过SBS能量反射率的变化可测定不同温度时的液体介质的运动黏度.在Countinuum Nd: YAG种子注入激光系统中测定了不同温度时的水的运动黏度并与运动黏度计测定的结果进行了比较.用本方法获得的不同温度时的水的运动黏度测量值与运动黏度计测量值很接近,相对误差小于5%. 关键词： 受激布里渊散射 SBS能量反射率 温度 运动黏度