检索结果-南通市图书馆

Chinese Physics Letters 1995年第9期12卷 537-540页

作者： WANG Hezhou ZHENG Xiguang MAO Weidong YU Zhenxin GAO Zhaolan institute for laser and spectroscopy Zhongshan UniversityGuangzhou 510275

The temporal behaviours of stimulated Rayleigh-wing scattering,at quasi-equilibrium and non-equilibrium of the molecular orientational distributions,are reported in this *** experimental results also show the relaxati... 详细信息

关键词： equilibrium Rayleigh relaxation

Er^(3+)/Yb^(3+)/Li^+/Zn^(2+):Gd_2(MoO_4)_3 upconverting nanophosphors in optical thermometry

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2019年第3期37卷 242-247页

作者： Anita Kumari Lakshmi Mukhopadhyay Vineet Kumar Rai laser and spectroscopy Laboratory Department of Applied Physics Indian Institute of Technology (Indian School of Mines)

Er^(3+)-Yb^(3+)-Li^+:Gd_2(MoO_4)_3 and Er^(3+)-Yb^(3+)-Zn^(2+):Gd_2(MoO_4)_3 nanophosphors, synthesized by chemical co-precipitation technique were characterized through XRD,FESEM,dynamic light scattering(DLS),diffuse reflectance, photoluminescence, photometric and decay time analysis. The enhancement of about～28, ～149 and ～351 times in the green upconversion emission band is observed for the optimized Er^(3+)-Yb^(3+),Er^(3+)-Yb^(3+)-Li^+ and Er^(3+)-Yb^(3+)-Zn^(2+):Gd_2(MoO_4)_3 nanophosphors in comparison to the singly Er^(3+) doped nanophosphors. The electric dipole-dipole interaction is found to be responsible for the concentration quenching. The temperature dependent behaviour of the two green thermally coupled levels of the Er^(3+) ions based on the fluorescence intensity ratio technique was studied. The maximum sensor sensitivity ～38.7 × 10^(-3) K^(-1) at 473 K for optimized Er^(3+)-Yb^(3+)-Zn^(2+) codoped Gd_2(MoO_4)_3 nanophosphors is reported with maximum population redistribution ability～88% among the ~2H_(11/2) and ~4S_(3/2) levels.

关键词： Upconversion Phosphors Dynamic light scattering Non-lanthanide ions Optical thermometry Rare earths

Parameters Optimization of laser-Induced Breakdown spectroscopy Experimental Setup for the Case with Beam Expander

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2015年第11期17卷 914-918页

作者：王鑫张雷樊娟娟李郁芳弓瑶董磊马维光尹王保贾锁堂 State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Laser SpectroscopyShanxi University

Improvement of measurement precision and repeatability is one of the issues currently faced by the laser-induced breakdown spectroscopy （LIBS） technique, which is expected to be capable of precise and accurate quantitative analysis. It was found that there was great potential to improve the signal quality and repeatability by reducing the laser beam divergence angle using a suitable beam expander （BE）. In the present work, the influences of several experimental parameters for the case with BE are studied in order to optimize the analytical performances： the signal to noise ratio （SNR） and the relative standard deviation （RSD）. We demonstrate that by selecting the optimal experimental parameters, the BE-included LIBS setup can give higher SNR and lower RSD values of the line intensity normalized by the whole spectrum area. For validation purposes, support vector machine （SVM） regression combined with principal component analysis （PCA） was used to establish a calibration model to realize the quantitative analysis of the ash content. Good agreement has been found between the laboratory measurement results from the LIBS method and those from the traditional method. The measurement accuracy presented here for ash content analysis is estimated to be 0.31%, while the average relative error is 2.36%.

关键词： laser-induced breakdown spectroscopy (LIBS) relative standard deviation(RSD) signal to noise ratio (SNR) beam expander (BE) support vector machine (SVM)

laser frequency locking based on Rydberg electromagnetically induced transparency

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2016年第5期25卷 132-134页

作者：焦月春李敬奎王丽梅张好张临杰赵建明贾锁堂 State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Laser Spectroscopy Shanxi University

We present a laser frequency locking to Rydberg transition with electromagnetically induced transparency（EIT）spectra in a room-temperature cesium vapor cell. Cesium levels 6S_（1/2）, 6P_（3/2）, and the n D_（5/2） state, compose a cascade three-level system, where a coupling laser drives Rydberg transition, and probe laser detects the EIT signal. The error signal, obtained by demodulating the EIT signal, is used to lock the coupling laser frequency to Rydberg transition. The laser frequency fluctuation, ~0.7 MHz, is obtained after locking on, with the minimum Allan variance to be 8.9 × 10^（-11）.This kind of locking method can be used to stabilize the laser frequency to the excited transition.

关键词： Rydberg electromagnetically induced transparency(EIT) laser locking

Er^(3+)-Yb^(3+)-Na^(+):ZnWO_(4) phosphors for enhanced visible upconversion and temperature sensing applications

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2021年第3期39卷 291-296,I0002页

作者： Sonali Biswas Lakshmi Mukhopadhyay Manisha Mondal Vineet Kumar Rai laser and spectroscopy Laboratory Department of PhysicsIndian Institute of Technology(Indian School of Mines)Dhanbad-826004JharkhandIndia

The crystal structure and surface morphology of the Er^(3+)/Yb^(3+)/Na+:ZnWO_(4) phosphors synthesized by solid state reaction method were analyzed by X-ray diffraction(XRD) and field emission scanning electron microscopy(FESEM) *** frequency upconversion(UC) emission study in the developed phosphors was investigated by using 980 nm laser diode *** effect of codoping in the Er^(3+):ZnWO_(4) phosphors on the UC emission intensity was *** UC emission bands that are exhibited in the blue(490 nm),green(530,552 nm),red(668 nm) and NIR(800 nm) region correspond to the ^(4)F_(7/2)→^(4)I_(15/2).^(2)H_(11/2),^(4)S_(3/2)→^(4)I_(15/2),^(4)F_(9/2)→^(4)I_(15/2) and ^(4)I9/2→^(4)I_(15/2) transitions,*** temperature sensing performance of the Er^(3+)-Yb^(3+)-Na+:ZnWO_(4) phosphors was investigated based on the 2 H_(11/2)→^(4)I_(15/2) and ^(4)S_(3/2)→^(4)I_(15/2) thermally coupled transitions of the Er^(3+)*** photometric study was also carried out for the developed phosphors.

关键词： Upconversion Non-lanthanides Temperature sensing Fluorescence intensity ratio Rare earths

OPTICAL STORAGE MECHANISM AND HIGH-ORDER DIFFRACTION PROPERTIES OF NITROAZOBENZENE-CONTAINING POLYESTER FILMS

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 1998年第1期16卷 67-74页

作者：颜星中魏雄罗挺蔡志岗梁兆熙余振新 State Key Lab of Ultrafast laser spectroscopy Zhongshan University Guangthou 510275 Institute of Polymer ScienceZhongshan University Guangzhou 510275 State Key Lab of Ultrafast laser spectroscopy Zhongshan University Guangthou 510275 State Key Lab of Ultrafast laser spectroscopy Zhongshan University Guangthou 510275 Department of Logistical Automatic EngineeringLogistical Engineering UniversityChangqing 630042

Using Nd:YAG second harmonic pulse (100 ps), the optical storage properties of two novel polyesters, poly [4'-bis (N, N-oxyethylene) imino-4-nitroazobenzene succinyl] and poly [2'-chloro-4'-bis (N, N-oxyethylene) imino-4-nitroazobenzene succinyl] have been studied by multiwave mixing. The high-order diffractions of the orientation gratings induced by anisotropy via the reorientation of nitroazobenzene groups and optical information storage with long-term stability have been realized by multiwave mixing in their films. Up to 3rd order forward diffraction was detected in two wave mixing, while up to 4th order backward diffraction was observed in degenerated four wave mixing. The recording mechanism was explained by the trans-cis-trans isomerization cycles of azobenzene groups. The isomerization of these azobenzene groups probably undergoes with inversion mechanism under the experimental conditions. The information recorded in these films has been kept for more than 6 months.

关键词： azobenzene-containing polyester multiwave mixing optical storage photoinduced anisotropy high-order diffraction of orientation grating

High-l Rydberg States＇ Interference Using a Double-Pulse Electric Field

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2014年第2期31卷 37-40页

作者：陈杰张好鲍善霞王丽梅张临杰李昌勇赵建明贾锁堂 State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Laser Spectroscopy Shanxi University Taiyuan 030006

The interference behavior of high-1 Rydberg states is investigated in external fields. We prepare high-l states from an initial excited ns Cs Rydberg state by applying one electric-field pulse. The interference between the initial ns state and the high-I states is investigated by two time-delayed short electric-field pulses. The state selective field ionization technique is used to measure the transfer ratio versus the field pulses parameters. The visibility of interference is defined to describe interference and the results show that a relative long duration of electric-field pulse will weaken the interference.

关键词： RYDBERG states ELECTRIC fields FIELD theory (Physics) FIELD ionization CHARGE transfer

THE SYNTHESIS OF NEW POLED CROSSLINKED POLYMETHACRYLATES AND THEIR SECOND ORDER NONLINEAR OPTICAL PROPERTIES

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 1996年第4期14卷 346-354页

作者：颜星中陈用烈梁兆熙蔡志岗杨佩青罗挺 institute of Polymer Science Zhongshan University Guangzhou 510275 State Key Lab of Ultrafast laser spectroscopy Zhongshan University Guangzhou 510275

Films were prepared from mixtures of copolymers of 4-nitro-4'-[N-methylacryloyloxyethyl, N'-ethyl] amino azobenzene with glycidyl methacrylate (chromophore content: 6 mol%) and copolymers containing anhydride units, which was obtained by the reaction of 4-nitro-4'-[N-hydroxyethyl, N'-ethyl] amino azobenzene with polymethacryloyl chloride (chromophore content: 25 mol %). During thermal poling process the anhydride reacts with the epoxy group and the resulting crosslinked network structure will stabilize the second harmonic generation in the poled film. The second harmonic generation of the poled film shows a maximum with the variation of composition this is presumed to be due to the effects of the increasing of concentration, orientation order as well as orientation stability of chromophore groups during crosslinking.

关键词： second order nonlinear optics poled polymers Disperse Red 1 methacrylate copolymers

Femtosecond Reflections of Bulk GaAs and GaAs/AlGaAs Multiple Quantum Wells

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 1996年第3期13卷 237-240页

作者： LI Wei-liang QIU Zhi-ren PENG Wen-ji HUANG Xu-guang ZHOU Jian-ying YU Zhen-xin State Key Laboratory of Ultrafast laser spectroscopy Zhongshan UniversityGuangzhou 510275

We present room temperature femtosecond rejection studies on the photocarrier dynamics of GaAs and GaAs/AlGaAs multiple quantum wells(MQW).A rising wing with a time constant of about.5 ps and an increased amplitude per carrier is observed for the MQW sample at carrier densities lower than 5×10^(11) cm^(-2).This phenomenon is explained as the saturation of the excitonic transitions.

关键词： GaAs/AlGaAs Femto Quantum

Pattern Formation and Quasicrystal Structure in Azobenzene Polymer Film

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2000年第6期17卷 428-430页

作者： XU Ze-Da CAI Zhi-Gang ZHANG Ling-Zhi LIU Yan-Fa YANG Jie SHE Wei-Long ZHOU Jian-Ying State Key Laboratory of Ultrafast laser spectroscopy Zhongshan UniversityGuangzhou 510275

Pattern formation in azobenzene polymer film by degenerate four-wave mixing is *** arrays with specific patterns are analyzed with scanning electron microscopy and polarizing optical *** is demonstrated that the control of photo-induced nanostructure sized micropattern in the nonlinear organic film is possible by using properly polarized writing beams with the total incident power exceeding a certain threshold.

关键词： film benzene exceeding