Determination of existing stress in silicon films on sapphire substrate using Raman spectroscopy

Raman spectroscopy is used to determine built-in stresses in silicon on sapphire (SOS) devices. The method is direct, nondestructive and can be applied at various temperatures. For epitaxial silicon films on sapphire substrates a built-in stress of 7.0±0.3 kbar at room temperature and 8.7±0.3 kbar at liquid nitrogen temperature was measured.     

壳层隔绝纳米粒子增强拉曼光谱测试系统设计

基于壳层隔绝纳米粒子增强技术,开发了一种新型的等离激元拉曼光谱测试系统,该系统能够有效地提高被测物质的拉曼反射信号强度。壳层隔绝纳米粒子增强技术采用包裹了极薄的二氧化硅或者氧化铝壳层的单层金纳米粒子,能够产生较强的表面增强效应。整个测试系统的硬件部分主要包括双处理器（ARM和DSP）主控板、半导体激光光源、光谱仪、光纤探头和粒子施加装置;软件部分能够自动获取被测物质的拉曼谱图。这里,粒子施加装置用于自动地将壳层隔绝纳米粒子施加到被测样本中。在实验中,将测试系统用于检测食品违禁添加物三聚氰胺和孔雀石绿,以验证壳层隔绝纳米粒子增强拉曼光谱技术。实验结果表明,该测试系统具有较高的测试灵敏度和较短的测试时间,广泛地适用于食品安全中痕量物质快速检测。     

相干反斯托克斯喇曼光谱

相干反斯托克斯喇曼光谱术(CARS)由于其高效率、高分辨率、对背景荧装置,光的抑制及相干反斯托克斯特性而具有明显的优点.已建成一套用于CARS的实验它采用由一个氮激光器泵浦的两台染料激光器,并用光电倍增管和积分平均器检测了输出信号.测得了1000厘米~(-1)附近的苯、甲苯和一系列卤素置换的苯衍生物的光谱.     

Optically heterodyned coherent Raman spectroscopy

A convenient variation of Raman-induced Kerr effect spectroscopy (RIKES) which overcomes many of the previous limitations of coherent Raman spectroscopy is introduced. Quantum limited signal-to-noise ratios may be approached by the use of optical heterodyne detection (OHD). Detector current, linearly proportional and phase sensitive to the third-order nonlinear susceptibility, and linearly proportional to the Raman scattering cross section, is produced. Heterodyne detection in coherent Raman spectroscopy enables the detection of weak Raman signals that would otherwise be obscured by noise resulting from background sources.     

蓝紫光的腔增强空气喇曼光谱

喇曼光谱是一种无损、快速检测物质成分的方法。为了提高监测灵敏度, 对408nm波段半导体激光器的腔增强自发喇曼散射进行了研究。利用输出功率500mW、线宽0.9nm的408nm半导体激光器作激发光, 把激光耦合入共焦球面镜腔, 两面共焦球面镜的反射率分别为96.5%和99.5%, 部分激光返回半导体激光器形成光反馈, 半导体激光器与共焦腔形成共振。对装置的光反馈过程进行了探讨, 并对外腔的模式匹配和频率匹配分别进行了分析。结果表明, 共焦腔内功率达到15W, 功率增强了30倍; 用90°探测构型收集喇曼信号, 完成了空气喇曼信号检测; 1s积分时间, 获得N₂信号900个计数。此共振增强腔大大增强了喇曼散射信号, 有潜力应用于多种气体的在线检测或高灵敏度检测。     

利伐沙班的定量检测:拉曼光谱法与远红外吸收光谱法

利伐沙班是一种新型口服抗凝药，它具有疗效确切、安全性好、使用方便等优点，所以经常用于静脉血栓栓塞性疾病的预防与治疗，以及非瓣膜性房颤的卒中预防。由于利伐沙班在患者体内的浓度会影响其对凝血因子Xa的抑制作用，这导致患者的临床反应有个体差异，影响最终治疗效果。为了更加合理地使用利伐沙班，临床上需要监测人体血液或尿液中利伐沙班的浓度。针对该临床需求，文中基于远红外指纹谱和拉曼特征谱在物质有效识别和定量分析的优势，采用傅里叶变换红外光谱仪和激光共聚焦拉曼光谱系统，针对液体状态下利伐沙班进行识别并定量检测。文中先通过傅里叶变换红外光谱仪检测利伐沙班的远红外吸收谱随其浓度发生的变化，再通过激光共聚焦拉曼光谱系统检测了利伐沙班的拉曼光谱随其浓度发生的变化，最后比较了远红外光谱法与拉曼法的准确率。经过比较，远红外检测的精度比拉曼光谱检测的精度提升2倍。这些结果对临床医学中利伐沙班的使用具有重要意义。     

激光喇曼光谱法诊断火焰

本文介绍了激光喇曼光谱法诊断火焰的基本原理和实验方法。运用该方法可以测得火焰的温度和物质浓度的三维空间场分布。实验结果与实际情况相符合。     

Ultrahigh sensitivity stimulated Raman gain spectroscopy

Using a synchronously pumped mode-locked dye laser system, we have obtained a factor of 300 improvement in signal to noise ratio (S/N) over previous CW experiments using stimulated Raman gain spectroscopy, and achieved anS/N = 200 000for a 1 s integration time in bulk benzene. This result confirms the sensitivity of the picosecond Raman gain approach and would allow the detection of a monolayer using a pump intensity of 100 MW/cm².     

喇曼光谱仪及其在疾病诊断中的应用

近年来喇曼光谱学在医学诊断中的研究与应用已得到迅速发展。在医学界利用光谱技术，进行疾病诊断已逐渐被人们所接受。本文重点描述了喇曼光谱及喇曼光谱仪的原理，并对喇曼光谱学在医学，尤其是癌症诊断中的新技术和新方法进行了综述。     

两种卟啉类光敏剂对SMMC-7721细胞敏化损伤的拉曼光谱分析

用拉曼光谱技术比较血卟啉单甲醚HMEM和血卟啉衍生物HpD对肝癌细胞SMMC-7721光敏化损伤。实验测定了用两种光敏剂对SMMC-7721细胞光动力作用后的DNA和蛋白质的光谱图。结果显示:HMME和HpD对DNA和蛋白质构象的光敏损伤特征是相同的,但损伤程度不同。经HMME作用的SMMC-7721细胞的谱线,DNA各峰的位置和强度的变化都比HpD大,有的峰消失,蛋白质主链的几条谱线强度与HpD谱线相比大幅降低,表示HMME对DNA和蛋白质主链的损伤较大。结果表明:HMME对SMMC-7721细胞的光敏     

Raman spectroscopy determination of composition and strain in heterostructures

A procedure for the quantitative measurement of composition and strain in epitaxial Si_1-xGe_x/Si heterostructures by means of Raman spectroscopy for any Ge concentration is presented. The calibration of the parameters of this procedure involved the growth of a set of heteroepitaxial layers spanning the range from pure Si to pure Ge. Different strain conditions were established in a highly controlled way by tailoring the substrate lattice parameter. Through the comparative analysis of reciprocal space mapping and Raman spectroscopy we obtained a set of parameters for the phonon energy variation due to biaxial deformation, as well as calibration curves for the dependence of the Raman band frequencies on alloy composition. With these new calibrations, Raman spectroscopy provides an accuracy in the determination of composition and strain comparable to that of X-ray diffraction, but with the added advantage of high-spatial resolution and resonance-induced surface confinement.     

基于复合超介质基板的微带天线设计与分析

利用方形开口谐振环、微带线和缺陷地结构建构了一种结构较为简单、便于调节的腔体型结构超介质.仿真结果表明,设计的超介质在1.0～3.6GHz、3.8～7.1GHz和7.2～8.0GHz三个频段内均具有等效介电常数和等效磁导率小于零的左手材料特性.将超介质单元周期性地镶嵌在一种普通多频微带天线的介质基板内,实现了基于复合超介质基板天线.测试结果表明,在工作频率为1.61,3.44和3.9GHz的微带天线中加载这种超介质结构覆层后,其谐振频率分别降低了60,70和40MHz,同时将4.53～4.80GHz和4.97～6.00GHz两个工作频段扩展为4.6～6.0GHz的超宽带.所设计的天线整体性能良好,且满足了WLAN在5GHz通信频段的要求.     

相干反斯托克斯喇曼光谱学(CARS)

本文就CARS原理、特性、有关实验方案及应用等方面作了介绍,并结合我们进行CARS工作的实际经验,讨论了CARS的发展前景和存在的问题.     

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。     

Surface vibrational spectroscopy using stimulated Raman scattering

We propose a new method for studying surface vibrational spectroscopy based on an extension of the picosecond stimulated Raman gain technique. This technique is extremely surface sensitive and can detect coverages of 1 percent of a monolayer. This technique does not require ultrahigh vacuums (as do electron spectroscopies), is an extremely sensitive probe of surface local fields, has very high frequency resolution (<1 cm^-1) and very short time resolution (∼ 1 ps).     

Identification of strained black phosphorous by Raman spectroscopy

Phosphorene has a very high hole mobility and can be a tuned band structure, and has become an ideal material for electronic devices. For this new type of two-dimensional material, in the applied strain, black phosphorus (BP) can be changed into an indirect band gap and metallic materials from the direct band gap semiconductor material, which greatly affect its inherent physical characteristics. How to identify strained microstructure changes becomes an important problem. The calculated Raman spectra disclose that the A_g² mode and B_2g mode will split and the Raman spectra appear, while the A_g¹ mode is shifted to low-frequency region. The deformation induced by strain will effectively change the Raman mode position and intensity, this can be used to identify phosphorus changes.     

胃癌组织拉曼光谱的研究

利用拉曼光谱仪得到了胃窦部正常组织和癌变组织的拉曼光谱。实验结果表明 :癌变组织的拉曼光谱中 10 89cm- 1 线比正常组织的明显增强 ,14 5 9cm- 1 线发生分裂。分析认为 :10 89cm- 1 处属于磷酸二酯基团中PO- 2 对称伸缩振劝谱带 ;14 5 9cm- 1 分别来源于脱氧核糖中 -CH2弯曲振动谱带、DNA胸腺嘧啶中CH3的对称变角振动谱带和DNA腺嘌呤、鸟嘌呤中的C =C -(接有电负性基团或极性基团 )。由于胃癌组织中细胞核内的NDA增多 ,细胞核肥大 ,核仁数增加 ;同时细胞中C =C -以及 -CH2 的双链上接有不饱和基团或电负性基团的数量增多 ,是造成胃癌组织拉曼光谱中 10 89cm- 1 线的增强 ,14 5 9cm- 1 线的分裂的可能原因。     

基于有源谐振腔的喇曼气体分析系统设计

为了检测、分析混合气体,根据混合气体中不同气体成分在喇曼频谱中各自的吸收谱峰,采用激光谐振腔增强光谱法原理和喇曼散射光谱技术,利用有源激光谐振腔和雪崩光电二极管,设计了针对于混合气体成分进行在线分析的实验系统。结果表明,对混合气体进行实时在线检测,可以有效检测出包含体积分数分别为0.502,0.498的N₂和O₂的混合气体。该系统操作便捷、安全可靠,可以实现混合气体的成分分析。     

Raman spectroscopy of amorphous carbon modified with iron

Raman spectroscopy has been employed to study spectra of the vibrational frequencies of carbon in the range 1000–1800 cm^?1 in amorphous carbon films modified with iron. The content of iron in a film has been set technologically by varying between the samples the area ratio of the graphite and iron parts of the target and monitored by Rutherford backscattering. Amorphous carbon layers containing 3, 26, 38, and 54 at. % iron have been obtained. The Raman spectra have the form of a broad band with features that are characteristic of amorphous carbon and lie at 1332 cm^?1 (D-band) and 1552 cm^?1 (G-band). At iron content of 38 and 54 at. %, the spectrum breaks up into a number of bands, which points to fragmentation of the matrix of amorphous carbon with increasing iron content. It is shown that the integral amplitude of scattering decreases nonlinearly with increasing iron content in a sample. The effect is analyzed in terms of a model that accounts for the linear dependence of the rate at which the number of atoms contributing to the scattering changes with the atomic fraction of carbon relative to the total number of carbon atoms in the film.