STUDY ON THE MICROSTRUCTURE AND PROPERTY OF PET FIBER BY LASER RAMAN MICROSCOPE

In this paper, the microstructure change of one step-draw PET fiber has been studied byvarious methods, such as, Laser Raman Microscope, Wide-angle X-ray, Density-gradient andPolarizing Microscope. The computer has been used to resolve overlapped bands in the Ramanspectra. Then the band changes have been correlated with trans, gauche and stressed trans-conformations indicated by a conformational index. Based on these indices, the relationshipbetween the conformation change of glycol units in the fiber structure and the macromechanicalproperties of fiber is expounded.

Laser Raman Spectrometry Study on Experimental Galactose-induced Cataract

Purpose:To observe the dynamic changes of hydration in galactose induced cataract.Methods:Two groups of wistar rats were used in the experiment.There were 12rats in the experimental group,which were fed diet of 50%D-Galactose standard feed;while the control group had8rats fed standard feed.Their other living conditions were the same,At desired time periods,two Wistar rats fed galactose and one normal control were selected and Killed20minutes before the instrument examination respectively,them,their lenses were repoved from the orbs by a posterior approach.The cleaned fresh lans was placed in a quartz cuvette with Tris buffered balanced salt solution containing5.5mmol/L glucose.The quartz cuvette was placed on the stage of the Spectroneter.The laser beam was focused at the lens nuclear fromthe bottom of the cuvette and the scattered light was col-lected at 90°to the incident beam.Results:Raman spectroscopy showed that(1)during the formation of galactose cataract,the Water signal(at3390cm-1)increased obiviously,and the ratio of I3390/I2935increased from0.31(3days)to2.26(17days).which is correlated with the imbibition of wter in the lens nuclear;（2）the hydration of lens nuclear could be divided into two phases.The ratio I3390/I2935was increased slowly and steadily by 11days after galactose feeding,Then,the ratio tured to increase quite fast till17days.Conclusion:The hydration of nuclear is changed simultaneously with the forman-tion of cataract,The hydration of nuclear is mainly due to the impalance of Na^+/K^+.Eye Science1995;11:143-146.

Laser Raman Spectroscopic Studies on Hemeproteins in Epileptic Children

Laser Raman spectroscopic studies were carried out on hemoproteins with special reference to epilepsy and compared the data with those of controls. Some of the bands were found approximately at 368.45 cm-1, 424.90 cm-1, 625.27 cm-1 and 807.38 cm-1 in case of normal children and at 1749.00 cm-1, 1795 cm-1 and 2000 cm-1 in epileptic children cases. A clear cut picture of the hemoproteins has already given in the literature and very interesting bands were found in the range from 300 cm-1 to 1800 cm-1. Our Raman lines are very effective and peculiar. We did not say anything about the detailing of these bands at this juncture.

Gigahertz frequency hopping in an optical phase-locked loop for Raman lasers

Raman lasers are essential in atomic physics,and the development of portable devices has posed requirements for time-division multiplexing of Raman lasers.We demonstrate an innovative gigahertz frequency hopping approach of a slave Raman laser within an optical phase-locked loop(OPLL),which finds practical application in an atomic gravimeter,where the OPLL frequently switches between near-resonance lasers and significantly detuned Raman lasers.The method merges the advantages of rapid and extensive frequency hopping with the OPLL’s inherent low phase noise,and exhibits a versatile range of applications in compact laser systems,promising advancements in portable instruments.

High-power linearly-polarized tunable Raman fiber laser

In this study, we demonstrate an all-fiber high-power linearly-polarized tunable Raman fiber laser system. An in- house high-power tunable fiber laser was employed as the pump source. A fiber loop mirror （FLM） serving as a high reflectivity mirror and a flat-cut endface serving as an output coupler were adopted to provide broadband feedback. A piece of 59-m commercial passive fiber was used as the Raman gain medium. The Raman laser had a 27.6 nm tuning range from 1112 nm to 1139.6 nm and a maximum output power of 125.3 W, which corresponds to a conversion efficiency of 79.4%. The polarization extinction ratio （PER） at all operational wavelengths was measured to be over 21 dB. To the best of our knowledge, this is the first report on a hundred-watt level linearly-polarized tunable Raman fiber laser.

Raman crystal lasers in the visible and near-infrared

Raman lasers based on potassium gadolinium tungstate and lead tungstate crystals pumped by a≈120 ps Nd: YAG laser at 1.064/μm were developed. High reflection mirrors for the Stokes wavelength have been used to generate near-infrared and eye safe spectral region of 1.15 - 1.32/μm. Second harmonic generation of the generated Raman lasers was observed. Eifficient multiple Stokes and anti-Stokes picosecond generation in 64 crystals have been shown to exhibit stimulated Raman scattering on about 700 lines covering the whole visible and near-infrared spectrum. All stimulated Raman scattering (SRS) wavelengths in the visible and near-infrared spectrum are identified and attributed to the SRS-active vibration modes of these crystals.

Q-Switched Raman Fiber Laser with Molybdenum Disulfide-Based Passive Saturable Absorber

We demonstrate a Q-switched Raman fiber laser using molybdenum disulfide （MoS2） as a saturable absorber （SA）. The SA is assembled by depositing a mechanically exfoliated MoS2 onto a fiber ferrule facet before it is matched with another clean ferrule via a connector. It is inserted in a Raman fiber laser cavity with a total cavity length of about 8kin to generate a Q-switching pulse train operating at 1560.2nm. A 7.7-kin-long dispersion compensating fiber with 584 ps.nm-i km-1 of dispersion is used as a nonlinear gain medium. As the pump power is increased from 395 m W to 422 m W, the repetition rate of the Q-switching pulses can be increased from 132.7 to 137.4 kHz while the pulse width is concurrently decreased from 3.35μs to 3.03μs. The maximum pulse energy of 54.3 nJ is obtained at the maximum pump power of 422 roW. These results show that the mechanically exfoliated MoS2 SA has a great potential to be used for pulse generation in Raman fiber laser systems.

LASER RAMAN SPECTROSCOPIC STUDY OF PHOTOSENSITIVE DAMAGE OF ANTICANCER DRUG YHPD TO DNA

A special dye-stuff was chosen and made to be absorbed by the cells of tumor, and then the cells were irradiated under a laser beam with a certain wavelength in order to cure cancer. This is known as laser-chemical therapy. Although photosensitization has been developed in the early 20th century and a number of works describing its effect

Modelling of passively Q-switched lasers with intracavity Raman conversion

We present a model of passively Q-switched Raman lasers by utilizing the rate equations. The intracavity fun-damental photon density, Raman photon density and the initial population-inversion density of the gain medium are assumed to be of Gaussian spatial distributions. These rate equations are normalized by introducing some synthetic parameters and solved numerically, and a group of general curves are generated. Prom these curves we can understand the dependence of the Raman laser pulse characteristics on the parameters about the pumping, the gain medium, the Raman medium and the resonator. An illustrative calculation for a passively Q-switched Nd^3＋：GdVO4 self-Raman laser is presented to demonstrate the usage of the curves and related formulas.

THE MOLECULAR MECHANISM OF PHOTOPORPHYRIN (YHPD)'S PHOTOSENSITIZATION——LASER RAMAN SPECTROSCOPIC STUDY OF MICROCOSMIC AND PHOTOSENSITIVE DAMAGE OF YHPD TO PROTEIN

Laser Raman spectroscopy was used to investigate the microcosmic and photosensitive damage of YHPD to lysozyme, of which the three-dimensional structure has been elucidated. The experimental results shown by various damages of the main-chain and side-chain of lysozyme are as follows: (ⅰ) Phe and Cys are also damaged by photosensitization of YHPD, except for Trp, Tyr, Met, 1/2Cys and His; (ⅱ) the order of the photosensitized sensitivity of various groups of these amino acids have been described; (ⅲ) Trp and Tyr buried in the three-dimensional structure of the protein are damaged very greatly, and (ⅳ) the main-chain conformation of the protein has changed considerably, such as a decrease in orderly structure (α-helix, β-sheet and β-turn) and a simultaneous increase in random coil.

Mid-Infrared Raman Fiber Lasers

As mid-infrared （MIR） lasers show numerous applications in the field of defense, medical, materials processing, and optical communications. Investigation on MIR Raman fiber lasers （RFL） increasingly becomes a hot topic. Compared with traditional silica fiber, fluoride and chalcogenide glass fibers possess higher nonlinear coefficients and excellent MIR transmittances. In this article, the latest development of the MIR RFL using fluoride and chalcogenide glass fibers as gain media are introduced, respectively. This review article mainly focuses on the development of MIR RFLs in aspects of output wavelength, output power and optical efficiency. The prospect of MIR RFLs is also discussed.

Efficient Diode-End-Pumped Actively Q-Switched Nd:YLF/SrWO4 Raman Laser

An efficient diode-end-pumped actively Q-switched Nd：YLF/SrW04 Raman laser is demonstrated. The fun- damental wave is 1047.0nm and the corresponding first-Stocks wave is 1158.7nm. With a pumping power of 10.5 W, the average output power of 2.2 W at 1158.7nm is obtained, with the corresponding optical conversion efficiency of 20.9%. At a repetition rate of 6 kHz, the pulse width of the Raman laser is 8. 7ns and the peak power is calculated to be 42.1 kW. The beam quality factors M2 in horizontal and vertical directions are 1.3 and 1.5, respectively.

Mode decoupling in solid state ring laser based on stimulated Raman effect in polar crystals

In this paper we study the gain saturation induced mode-coupling control in solid state ring laser devices based on the stimulated Raman effect of the polar crystals in.order to realize solid state ring laser gyroscopes. We theoretically investigate the mode coupling induced by gain saturation between clockwise （CW） and counterclockwise （CCW） propa- gating laser modes. Because the CW and CCW running waves are pumped with counter-propagating lasers respectively, the independent coexistence can be ensured.

1400-1500 nm,Different Material-doped Raman Fiber Lasers Pumped by Nd∶YVO_4 Laser

Different material-doped Raman fiber lasers with very high efficiency operating in continuous-wave are presented.With 1 W Nd∶YVO 4 laser pumping at wavelength of 1 342 nm, single mode output power of above 500 mW (optical-to-optical conversion efficiency of 50%) is simulated in the range of 1 400-1 500 nm.Using high-germanium,high-phosphate and high-borate silicate fibers as the gain medium,laser output at wavelengths of 1 420,1 450,1 480 and 1 495 nm can be achieved with different geometries,which are just as pumping C-band and L-band distributed Raman fiber amplifiers.

Efficient Diode-Pumped Actively Q-Switched Ceramic Nd:YAG/YVO4 Raman Laser Operating at 1657 nm

A diode-pumped actively Q-switched Raman laser is demonstrated, with YV04 employed as Raman active medium, based on a ceramic Nd：YAG laser operating at 1444nm. The first-stokes Raman generation at 1657nm is achieved. A maximum output power of as high as 612mW is obtained under a pump power of 20. 7 W and at a pulse repetition frequency rate of 20kHz, corresponding to an optical-to-optical conversion efficiency of 3%.

Multi-wavelength continuous-wave Nd:YVO4 self-Raman laser under in-band pumping

Multi-wavelength continuous-wave self-Raman laser with an a-cut composite YVO4/Nd:YVO4/YVO4 crystal pumped by an 879-nm wavelength-locked laser diode is demonstrated for the first time.Multi-wavelength Raman lasers at 1168.4,1176,1178.7,and 1201.6 nm are achieved by the first Stokes shift of the multi-wavelength fundamental lasers at 1064,1066.7,1073.6,1084,and 1085.6 nm with two Raman shifts of 890 and 816 cm^-1.A maximum Raman output power of 2.56 W is achieved through the use of a 20-mm-long composite crystal,with a corresponding optical conversion efficiency of 9.8%.The polarization directions of different fundamental and Raman lasers are investigated and found to be orthogonalπandσpolarizations.These orthogonally polarized multi-wavelength lasers with small wavelength separation pave the way to the development of a potential laser source for application in spectral analysis,laser radar and THz generation.

准噶尔盆地征沙村地区三叠系储层沥青赋存特征及成因探讨

准噶尔盆地是我国西部典型的叠合盆地,油气资源丰富。近年来在腹部二叠—三叠系多口探井获得了工业油气流,展现了盆地深层—超深层巨大的油气勘探潜力(刘惠民等,2023)。中国石化在准噶尔盆地腹部征沙村地区钻探的征10井,在井深超过6500 m的三叠系、二叠系储层分获工业油气流。岩芯观察及薄片分析表明.

Origin of the Yueguang gold deposit in Xinhua, Hunan Province, South China: insights from fl uid inclusion and hydrogen–oxygen stable isotope analysis

The Yueguang gold deposit is located in Fengjia,Xinhua County,Hunan Province,South China.It represents a recently discovered small-scale gold deposit situated in the southwestern region of the Jiangnan Orogenic Belt,west of the Baimashan granitic batholith.In order to discern the characteristics of the ore-formingfluids,the underlying mineralization processes,and establish a foundation for the origin of the Yueguang gold depositfluid inclusion micro-thermometry,as well as quartz hydrogen and oxygen isotope analysis,have been carried out on samples obtained from various stages of mineralization.The hydrothermal miner-alization stages within the Yueguang gold deposit can be categorized into three stages:(i)the barren,pre-ore quartz-pyrite stage(Stage Ⅰ),the quartz-pyrite-gold stage(Stage Ⅱ),and the post-ore quartz-carbonate stage(Stage Ⅲ),with the second stage being the main mineralization stage.Thefluid inclusions identified in samples from the main min-eralization stage can predominantly be described with the NaCl–H_(2)O and CO_(2)–NaCl–H_(2)O systems.These inclusions display homogenization temperatures ranging from 158.8 to 334.9℃,and thefluid salinity ranges from 0.3%to 4.0%(wt.%NaCl equiv.).Laser Raman spectroscopy analysis of individual inclusions further reveals the presence of gas-phases such as CO_(2),CH_(4),and N_(2).Isotopic analysis indicatesδ^(18)Ofluid values ranging from 3.95 to 6.7‰ and δDH_(2)O values ranging from-71.9 to-55.7‰.These results indi-cate that the ore-formingfluid of the Yueguang gold deposit belongs to metamorphic hydrothermalfluids of middle-low temperature and low salinity.In the process of ore formation,gold is transported in the form of Au(HS)2-complexes,with gold deposition being driven byfluid immiscibility.Therefore,the Yueguang gold deposit is categorized as an orogenic gold deposit dominated by metamorphic hydrother-malfluid.It may become a new target for gold exploration in the Baimashan region,central Hunan Province.

Raman Spectra of Laser Crystals NAB and NYAB and the Ligand Vibrations of Their Active Ions

The lattice vibration mode of the laser crystals NAB and NYAB are measured by Raman spectra method and the possible effects of the BO3 and NdO6 vibration modes on the non-radiative transition of the active ions are discussed.

时间门控拉曼光谱仪的原理与技术发展历史及其应用

时间门控拉曼光谱(TGRS)已被证明是解决荧光对拉曼信号干扰最有效的方法之一。自早期大型昂贵实验室设备(如光学克尔门)诞生以来,至今荧光抑制技术已取得了长足进步。如今,有更好更经济实惠的小型设备可供选择使用。这些精进主要归功于光谱仪和电子元件生产技术的进步,从而降低了设备的复杂性和成本。时间门控拉曼光谱仪的关键组成部分是精确的时间同步(皮秒范围),即脉冲激光激发源与灵敏快速的检测器之间的同步。在激光脉冲期间,检测器能够收集拉曼信号,而在检测器的关闭期间,由于荧光发射具有更长的延迟时间,因此可以将其排斥。由于其较短的测量周期,TG拉曼光谱还具有对环境光和热辐射的抗干扰能力。近年来,超灵敏快速探测器的研究重点集中在门控和增益型电荷耦合器件(ICCDs)上,或者集中在CMOS单光子雪崩二极管(SPADs)阵列上,这些器件同样适用于进行TG拉曼。与门控CCDs相比,SPADs阵列具有更高的灵敏度和更好的时间分辨率,并且不需要过度冷却探测器。本文旨在回顾从早期至今国内外TG Raman技术的技术发展成果,并且介绍用TG Raman技术研究纳米二氧化锡颗粒和指甲实验结果,并且还简要讨论TG技术可能的扩展应用。