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 be...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.展开更多
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-G...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.展开更多
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-...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.展开更多
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 appro...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.展开更多
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） servi...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.展开更多
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 gener...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.展开更多
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 i...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.展开更多
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 th...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展开更多
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 mediu...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.展开更多
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 d...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.展开更多
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 ...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.展开更多
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 ...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.展开更多
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 gyroscop...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.展开更多
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 (op...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.展开更多
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 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%.展开更多
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...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.展开更多
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,w...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.展开更多
The lattice vibration mode of the laser crystals NAB and NYAB are measured by Raman spectra method and the possible effects of the BO<sub>3</sub> and NdO<sub>6</sub> vibration modes on the non-...The lattice vibration mode of the laser crystals NAB and NYAB are measured by Raman spectra method and the possible effects of the BO<sub>3</sub> and NdO<sub>6</sub> vibration modes on the non-radiative transition of the active ions are discussed.展开更多
文摘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.
文摘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.
文摘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.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2021YFA0718300 and 2021YFA1400900)the National Natural Science Foundation of China(Grant Nos.11920101004,11934002,and 92365208)+1 种基金Science and Technology Major Project of Shanxi(Grant No.202101030201022)Space Application System of China Manned Space Program.
文摘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.
基金Project supported by the Fok Ying-Tong Education Foundation,China(Grant No.151062)
文摘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.
文摘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.
文摘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.
基金Project supported by the National Natural Science Foundation of China
文摘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
基金Project supported by the National Natural Science Foundation of China （Grant No 60478017）, the Science and Technology Development Program of Shandong Province, China and the Scientific Research Starting Foundation for Returned 0verseas Chinese Scholars, Ministry of Education, China.
文摘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.
基金Project supported by the National Natural Science Foundation of China.
文摘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.
基金supported by the Fundamental Research Funds for the Central Universities under Grant No.ZYGX2015KYQD015
文摘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.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11204160,61378032 and 61211120196the Shandong Province Science and Technology Research Projects under Grant No 2010GGX10137
文摘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.
文摘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.
文摘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.
基金Supported by the Foundation of the State Key Laboratory of Crystal Material of Shandong University under Grant No KF1101the Foundation of Shandong University under Grant No 1170072613176+2 种基金the National Natural Science Foundation of China under Grant Nos 11004122 and 11204160the Special Grade of China Postdoctoral Science Foundation under Grant No 201104627the Independent Innovation Foundation of Shandong University under Grant No 2011GN058
文摘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%.
基金Project supported by the National Natural Science Foundation of China(Grant No.11774301)the Young Scientists Fund of the National Natural Science Foundation of China(Grant No.11804292)
文摘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.
基金support from several sources,including the Backbone Teacher Training Program(10912-SJGG2021-04233)the Teaching Reform Project of Chengdu University of Technology(JG2130131)+1 种基金the University-Industry Collaborative Education Project,Ministry of Education,China(22097130210756)National Natural Science Foundation of China(42272129).
文摘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.
文摘The lattice vibration mode of the laser crystals NAB and NYAB are measured by Raman spectra method and the possible effects of the BO<sub>3</sub> and NdO<sub>6</sub> vibration modes on the non-radiative transition of the active ions are discussed.
