Micro‐Raman Scattering Imaging of Langmuir–Blodgett Surface Relief Gratings

Surface relief gratings (SRGs) recorded on Langmuir–Blodgett (LB) films of an azobenzene homopolymer were visualized using micro‐Raman imaging. Raman scattering (RS) was achieved using the 780 nm laser line while pre‐resonance Raman scattering (pre‐RRS) and resonance Raman scattering were achieved using the 633 and 514.5 nm laser lines, respectively. Pre‐surface‐enhanced resonance Raman scattering (pre‐SERRS) and surface‐enhanced resonance Raman scattering (SERRS) were collected for the LB films covered with a 6 nm thick silver island film. The SRG could be chemically identified by the spatial variation in the Raman signal scattered by the film due to a concentration gradient. The pre‐SERRS provided signals of the same intensity along and across the grooves, indicating that the molecular architecture at the SRG surface is the same at the peaks as in the valleys.     

Optical properties of porous nanosized GaAs

The optical properties of porous GaAs layers obtained by electrochemical etching of single-crystal n-and p-GaAs(100) wafers are studied. It is shown that the shape of the nanocrystals, their mean diameter, and their surface states depend on the conductivity type of the initial crystal. A shift of the peaks corresponding to the main optical phonons to lower frequencies in the Raman spectra is observed. Surface-phonon frequencies determined from the Raman spectra coincide with those determined from the reflection spectra in the infrared spectral region. The forms of the spectral dependences of the reflection coefficient in the phonon-resonance region in bulk GaAs differ from those in porous GaAs. This is caused by the appearance of additional oscillators related to spatially confined lattice vibrations in GaAs nanocrystals. Atomic-force microscopy is used to study the surface morphology of porous GaAs samples formed on the n-GaAs substrates, and a nanosized surface profile is observed. Estimations made for the mean diameter of GaAs nanocrystals based on data from the Raman scattering, infrared spectroscopy, photoluminescence, and atomic-force microscopy yield results that are in good agreement with each other.     

乳腺癌氧合血红蛋白表面增强拉曼光谱研究

采用重复性及生物兼容性较好的二维纳米银膜作为氧合血红蛋白表面增强拉曼散射光谱的（SERS）基底，利用具有较好匹配的近红外激光作为激发光源，通过引起共振拉曼效应分别对健康女性和女性乳腺癌患者的氧合血红蛋白进行SERS光谱研究。比较两组氧合血红蛋白平均SERS光谱，发现存在差异。利用SPSS软件的主成分分析（PCA）方法和独立变量T检验统计分析方法，发现两组光谱在659、813和1 122 cm-1拉曼频移处的谱峰有着极显著的区别。对主成分进行归属分析，女性乳腺癌患者氧合血红蛋白分子中，吡咯环的反对称变形振动、对称变形振动以及吡咯环的呼吸振动的强度、相对于健康女性显著减少，从而造成图谱谱峰有明显差异。除此以外，SERS技术结合SPSS统计分析方法能够较好地区分健康女性和乳腺癌患者的氧合血红蛋白，从而有望发展成为一种新型的乳腺癌临床诊断技术。     

基于最近邻比较和中值滤波的拉曼光谱spike自动检测及剔除方法研究

激光拉曼光谱技术具有原位、实时、多物质同时探测的优点,在实验室内已经得到了广泛研究,并逐渐应用于深海海底等极端环境下的原位探测。由于CCD等光谱探测器可能受到宇宙射线的干扰,会在拉曼谱图上形成位置随机的spike,对拉曼光谱分析造成干扰。将最近邻比较和中值滤波相结合的方法应用于海水实测拉曼光谱spike的检测剔除,首先将原始拉曼光谱分为拉曼峰区域和非拉曼峰区域,对拉曼峰区域使用最近邻比较法处理,对非拉曼峰区域使用中值滤波方法,结果显示该方法能将非拉曼峰区域和拉曼峰区域的spike完全剔除,没有出现误检和漏检,且不会对拉曼特征峰强度产生影响,有助于提高拉曼光谱定性定量分析的精确性和稳定性。     

硫氰酸铵溶液的喇曼光谱理论与实验研究

为了研究硫氰酸铵溶液的喇曼光谱特征,采用Hartree-Fock方法在6-31G(d)基组水平上对硫氰酸根离子的几何结构进行了优化,并在此基础上计算了该离子的喇曼光谱,实验中测量了不同浓度的硫氰酸铵溶液的喇曼光谱,发现SCN-的浓度和对应的喇曼峰强度间存在线性关系。结果表明,SCN-的喇曼振动基频实验值(752cm-1)与理论值(740cm-1)的绝对偏差和相对误差都较小,而另一喇曼特征区域则出现不同程度的包络。该研究结果将有助于工业上硫氰酸铵溶液含量的测试。     

基于虚拟仪器的激光光斑自动采集与分析系统

为了得到激光光束的某些参量,为设计和改进激光器提供依据,建立了一套激光光斑自动采集与分析系统,搭建了实验平台,并编写了一套基于虚拟仪器开发平台LabVIEW及其图像处理软件包NI Vision的用于采集和分析激光光斑的软件。该软件能实时显示光斑中心位置的漂移轨迹、在x方向和y方向漂移的标准差及其随时间变化的趋势等,同时,还能对基模高斯光束进行分析。经过去噪处理的光斑图样能以3维灰度图的形式显示出来,得到任意剖面的光强信息,并以此进行高斯曲线拟合,得出拟合参量以判断光强曲线接近高斯曲线的程度。结果表明,这种系统可以动态地采集光斑信息并进行处理,具有实时性。     

Determination of the spectral width of Raman gain regions for different far infrared laser gases using a metal mesh Fabry Pérot interferometer

In this paper we report on the determination of the spectral width of Raman gain regions for different far infrared laser gases using a metal mesh Fabry Pérot interferometer. By use of broadband pump radiation emitted from a high pressure CO₂ laser we generated far infrared radiation within the Raman gain regions via stimulated Raman scattering. The spectral width of the far infrared radiation was determined using a Fabry Pérot interferometer in high interference order. We applied the method to study stimulated Raman scattering in D₂O and methylfluoride at different gas pressures.     

苯、吡啶及吡嗪分子的超拉曼和表面增强超拉曼光谱

用量子化学从头算法计算了苯、吡啶及吡嗪分子的超粒曼和表面增强的超拉曼光谱，并比较了理论计算与实验测量的结果，用Gaussian98中的密度泛函的方法计算分子的偶极矩、极化率和超极化率以及偶极矩、极化率的导数，而超极化率的导数则有限差分的方法来计算，为了检验有限差分法的准确性，用该方法计算了上述分子的红外和拉曼光谱，其结果与Gaussian98的计算结果高度一致，建立了基于有限差分法计算分子红外，拉曼，表面增强拉曼。超拉曼和表面增强超拉曼的光谱强度的方法，并编写了计算程序。     

Vibrational spectra of CuInS2x Se2(1−x) solid solutions

The reflection spectra in the infrared range and the optical Raman spectra are investigated in single crystals of the ternary compounds CuInS₂ and CuInSe₂ and in CuInS_2x Se_2(1−x) solid solutions, all grown by the method of chemical transport reactions. The frequencies of the optical modes in the given materials are determined, and the type of behavior of these modes in the solid solutions are established. Fiz. Tekh. Poluprovodn. 31, 49–52 (January 1997)     

拉曼光谱在红宝石检测中的应用研究

本文采用显微共焦拉曼光谱仪(785nm)对典型的天然、处理、合成红宝石,以及一些相似红宝石进行了测定.经分析,可知刚玉族宝石的特征拉曼位移在378,417,430,447,576,645和750cm-1附近,其中417cm-1显示最强的光谱特征.一些矿物包体可根据其特征拉曼位移而被检测出,如方解石在1085cm-1附近,这样对天然红宝石的鉴定和产地分析具有一定的参考意义.对于铅玻璃充填的红宝石,在1353cm-1附近具有一强且宽的拉曼峰,通过XRF的定量分析可测得高含量的铅;另外,发现红宝石中被充填了有机胶,拉曼位移在2331,2874和3285cm-1附近.一些合成红宝石的拉曼光谱中可能存在一强且对称的荧光背景,这可能与合成过程中添加了含有过渡族或稀土离子的助熔剂有关.相似的红色宝石具有与红宝石明显不同的拉曼光谱特征,较易鉴别.     

The influence of rf induced bias on the properties of diamond-like carbon films prepared using ECR-CVD

The deposition of diamond-like carbon (DLC) films from a mixture of hydrogen and methane using the electron resonance chemical vapor deposition (ECR-CVD) method with radio-frequency (rf) bias is reported. The structural characteristics of the DLC films were characterized using Raman spectroscopy. The effects of the self-generated dc bias resulting from the rf power on the optical gap, Raman spectra, infrared (IR) absorption, and film hardness in depositions carried out at 7 and 15 mTorr process pressures were investigated. Under conditions of 100 W microwave power and for dc bias variation ranging from −10 to −200 V, there is evidence from Raman scattering analysis to show an increase in the DLC-like characteristic in films deposited at low dc bias at both process pressures. The variation of the D and G line peak position and intergrated intensity ratio (I_D/I_G) in the Raman spectra correlates well with the film hardness profile. There does not seem to be a relationship between the variation of the C-H absorption peak intensity in the IR spectra (bonded hydrogen content) and the optical gap, although films with the highest optical gap tend to show a relatively higher C-H absorption peak intensity in the IR spectra. Films deposited at high dc bias showed a reduction in the C-H infrared absorption, suggesting a reduction in the bonded hydrogen content.     

显微共焦拉曼技术对有机-无机充填红宝石的表征

基于显微共焦拉曼光谱仪(785nm)、XRF和红外光谱仪对有机-无机充填红宝石进行了测试,分析得出1353cm-1附近FWHM达500cm-1的拉曼位移是由红宝石裂纹中的无机充填物质-铅玻璃所引起;而充填有机物的红宝石可能会在高频区出现2331cm-1,2874cm-1和3285cm-1拉曼位移,同时产生2927cm-1和2856cm-1红外吸收带等与有机相关的吸收谱带.     

地物目标热红外光谱发射率的野外测量方法研究

在航天红外遥感应用中,地物目标光谱发射率是卫星遥感测量地面温度的一个重要参数。野外测量的大气环境、目标背景和地物的热力学特性等因素的影响,使得野外测量地物目标表面光谱发射率变得较为复杂。重点讨论了利用傅里叶变换红外光谱仪野外测量地物目标光谱发射率的方法和程序,介绍了几种正确分离目标温度与发射率的方法。野外测量实验结果表明,按照文中所述的测量方法,测量得到的地物热红外光谱发射率具有良好的一致性,发射率测量误差小于0．02。     

心律失常患者红细胞的光镊拉曼光谱

利用激光光镊拉曼光谱系统,测定健康者红细胞(RBC)和心律失常患者红细胞的拉曼光谱,对健康者红细胞与心律失常患者红细胞的拉曼光谱进行了比较,发现心律失常患者红细胞的部分谱线整体强度有所减弱,部分谱线发生了频移;另外,低强度He-Ne激光对心律失常患者红细胞也存在一定的影响.根据拉曼光谱差异性,进一步探讨其红细胞内容物的...     

低红外发射率黏合剂聚异戊二烯/丙烯腈的制备研究

以异戊二烯(IP)、丙烯腈(AN)为共聚单体、乙二醇二甲基丙烯酸酯(EGDMA)为交联单体、十二烷基硫酸钠(SDS)和烷基酚聚氧乙烯醚(TX-30)为复合乳化剂、过氧化羟基异丙苯(CHP)-硫酸亚铁为氧化还原引发体系,采用乳液聚合法合成了热红外隐身涂层用聚异戊二烯/丙烯腈黏合剂。采用红外光谱仪(FT-IR)、场发射扫描电子显微镜(ESEM)、红外发射率测试仪等对共聚物的结构和红外性能进行了表征。研究了共聚物的红外光谱,比较了共聚物和三元乙丙橡胶(EPDM)在8～14μm的红外吸收,并研究了共聚物中交联单体比例对共聚物在8～14μm波段的红外吸收和红外发射率的影响。结果表明:聚异戊二烯/丙烯腈黏合剂在8～14μm波段红外基本透明,红外发射率0.82,能应用于热红外隐身涂层。     

Forest canopy closure from classification and spectral unmixing ofscene components-multisensor evaluation of an open canopy

Three types of remote sensing data, color infrared aerial photography (CIR), compact airborne spectrographic imager (CASI) imagery, and airborne visible/infrared imaging spectrometer (AVIRIS) imagery, have been used to estimate forest canopy closure for an open-canopy forest environment. The high-spatial-resolution CIR and CASI images were classified to generate forest canopy closure estimates. These estimates were used to validate the forest canopy closure estimation accuracy obtained using the AVIRIS image. Reflectance spectra extracted from the spectral-mode CASI image were used to normalize the raw AVIRIS image to a reflectance image. Classification and spectral unmixing methods have been applied to the AVIRIS image. Results indicate that both the classification and the spectral unmixing methods can produce reasonably accurate estimates of forest canopy closure (within 3 percent agreement) when related statistics are extracted from the AVIRIS image and relatively pure reflectance spectra are extracted from the CASI image. However, it is more challenging to use the spectral unmixing technique to derive subpixel-scale components whose reflectance spectra cannot be directly extracted from the AVIRIS image     

Na_5Eu(WO_4)_4发光晶体的光谱特性研究

对稀土四钨酸盐的研究很早就有报道,但作为发光材料的研究是近十几年才逐渐增多的.Na_5Eu(WO_4)_4作为该系列红外发光材料,近几年也有不少研究报道.陈立高、施潮淑等人改进了Na_5Eu(WO_4)_4的发光性能,黄京根等人指出Na_5Eu(WO_4)_4是良好的微晶激光材料.但是到目前为止,研究尚限于粉末材料.我们进行了Na_5Eu(WO_4)_4单晶制备的研究工作,已报道用助熔剂泡生法首次成功地生长出了Na_5Eu(WO_4)_4单晶,尺寸为2×1×1mm~3,并进行了结构分析.本文报道用助熔剂缓冷法生长出长度达4.5mm的Na_5Eu(WO_4)_4单     

头发光谱显微成像数据处理分析方法及其应用

随着多通道探测技术、集成显微技术和计算机及分析技术的发展,红外和拉曼光谱技术及光谱显微成像技术在生物及医学领域得到广泛应用并成为一种向实用化发展的趋势。但是,要从光谱测量中获得准确、有用的信息需要对光谱及成像数据进行细致、合理的分析。本文工作应用MATLAB软件编程,结合单谱线分析和多谱线多变量分析的方法,对健康人和病人头发横截面微观扫描的拉曼光谱数据进行分析,结果表明,通过对头发拉曼光谱细致处理和数据分析可以揭示被检测人之间的差异。这项工作是把拉曼光谱成像技术及相关光谱分析方法应用于生物医学领域的一个实例。     

Optical properties of cubic SiC grown on Si substrate by chemical vapor deposition

A series of 3C-SiC films with varied film thickness up to 17 μm have been grown on Si(1 0 0) by chemical vapor deposition, and studied by photoluminescence, Raman scattering, Fourier transform infrared transmission and reflectance measurements. Typical key behaviors on these optical spectra are investigated. Thinner (<3 μm) films have their optical spectral features, mainly associated with defects. High quality of single crystalline cubic SiC materials can be obtained from thicker (>10 μm) films, evidenced by optical spectra. There exists a tensile stress in the 3C-SiC film grown on Si, affecting greatly the optical features. Its measurements have leaded to a formulas on two deformation potentials, a and b.     

黄色蛇纹石玉的谱学特征研究

通过运用X射线荧光光谱、紫外-可见吸收光谱、差热分析、红外光谱和拉曼光谱测试对少见的黄色蛇纹石玉进行成分和结构的分析,结果表明其主要成分为利蛇纹石。利蛇纹石的红外光谱具有由Si-O伸缩振动引起的956cm-1,1080cm-1,3650cm-1肩吸收的特征吸收峰。少见的黄色经紫外-可见吸收光谱测定得出363nm,384nm吸收峰,主要是由杂质离子Fe3+离子的d-d晶场跃迁引起。经过高温加热处理后,蛇纹石玉失去结构水转变为新的物相镁橄榄石,拉曼峰825m-1和856cm-1是镁橄榄石的特征谱峰。由热处理法