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High energy optically pumped NH_3 terahertz laser with simple cavity

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Chinese Optics Letters 2010年第4期8卷 411-413页

作者：苗亮左都罗纠智先程祖海祁春超吴君竹 Wuhan National Laboratory for Optoelectronics College of Optoelectronic Science and Engineering Huazhong University of Science and Technology

A high energy pulsed terahertz（THz） laser is studied *** laser cavity simply consists of a quartz glass waveguide,a coated GaAs input window,and a crystal quartz output ***3 is filled in the cavity as gain medium,and pumped by an 8-J line-tunable transversely excited atmospheric（TEA） CO_2 *** 9R（16） transition acts as the pump line,55.6-mJ THz radiation（90μm） is obtained at 730-Pa NH_3 *** corresponding conversion efficiency is 13.54%.Energy and optimal pressure of amplified spontaneous emission and laser oscillation are compared.

关键词： Conversion efficiency Glass lasers High energy physics Infrared lasers Oxide minerals pulsed laser applications pulsed lasers Quartz

Characteristics of Plasma Shock Waves Generated in the pulsed Laser Ablation Process

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Chinese Physics Letters 2002年第12期19卷 1841-1843页

作者：李智华张端明等 NationalKeyLaboratoryofLaserandDepartmentofPhysics HuazhongUniversityofScienceandTechnologyWuhan430074 NationalKeyLaboratoryofLaserandDepartmentofPhysics HuazhongUniversityofScienceandTechnologyWuha

We modify the Sedov theory to describe plasma shock waves generated in a pulsed laser ablating process. We also study the propagation characteristics of plasma shock waves during the preparation process of functional thin films deposited by a pulsed laser. In particular, We discuss in detail the temporal behaviour of energy causing the difference of the propagation characteristics between the plasma shock wave and the ideal shock wave in point explosion model. Under the same experimental conditions, the theoretical results calculated with our modified Sedov theory are in good agreement with the existent experimental data.

关键词： pulsed lasers

Broadband terahertz spectroscopy

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Chinese Optics Letters 2011年第11期9卷 40-45页

作者：范文慧 State Key Laboratory of Transient Optics and Photonics Xi'an Institute of Optics and Precision MechanicsChinese Academy of Sciences

An overview of the major techniques to generate and detect THz radiation so far,especially the major approaches to generate and detect coherent ultra-short THz pulses using ultra-short pulsed laser,has been *** also,this paper,in particularly,focuses on broadband THz spectroscopy and addresses on a number of issues relevant to generation and detection of broadband pulsed THz radiation as well as broadband time-domain THz spectroscopy （THz-TDS） with the help of ultra-short pulsed *** time-domain waveforms of coherent ultra-short THz pulses from photoconductive antenna excited by femtosecond laser with different pulse durations and their corresponding Fourier-transformed spectra have been obtained via the numerical simulation of ultrafast dynamics between femtosecond laser pulse and photoconductive *** origins of fringes modulated on the top of broadband amplitude spectrum,which is measured by electric-optic detector based on thin nonlinear crystal and extracted by fast Fourier transformation,have been analyzed and the major solutions to get rid of these fringes are discussed.

关键词： Excitons Fourier analysis Fourier transforms Microwave antennas Photoconductivity pulsed lasers Terahertz waves Time domain analysis Ultrafast lasers Ultrashort pulses

Propagating Properties of Cylindrical Rayleigh Waves Generated by a pulsed Laser Line Source

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Chinese Physics Letters 2004年第7期21卷 1294-1297页

作者： HUWen-Xiang QIANMeng-Lu InstituteofAcoustics TongjiUniversityShanghai200092

A two-dimensional theoretical model is used to analyse the acoustic field of cylindrical surface waves generated by a pulsed laser line source in the ablation regime. The complete dispersive curves for cylindrical Rayleigh wave are presented. The laser-generated transient acoustic field of cylindrical Rayleigh waves is calculated and the corresponding laser ultrasonic experiments are carried out. Both the numerical and experimental results are in good agreement.

关键词： Cylindrical Propagating surface waves line source acoustic field Rayleigh waves pulsed lasers

Generation of Femtosecond Laser Pulse at 1053 nm with Contrast of 10-11 by Optical-Parametric Amplification

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Chinese Physics Letters 2014年第1期31卷 96-98页

作者：沈忠伟王兆华张伟范海涛滕浩魏志义 Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190

A high contrast 1053nm femtosecond laser pulse with free background is demonstrated based on non-collinear optical-parametric amplification （NOPA）. By permuting the signal and idler in two stages of NOPAs, 48.2fs, 62 μJ laser pulse at 1053nm with contrast ratio of 2.3 ×10^-11 is obtained within the time scale of sub-5 ps. The beam quality factors M2 for tangential and sagittal directions are 1.59 and 1.30, respectively. This work not only proves a feasible way to generate a clean femtoseeond laser pulse but can also be employed as an ideal frontend for ultrashort ultrahigh intensity Nd：glass-based laser systems.

关键词： LASER pulses LASER beams pulsed lasers LASER pulse modes FEMTOSECOND lasers

Passively Q-Switched Tm,Ho：YVO4 Laser with Cr：ZnS Saturable Absorber at 2 μm

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Chinese Physics Letters 2014年第6期31卷 125-128页

作者：杜艳秋姚宝权崔铮段小明戴通宇鞠有伦潘裕柏陈敏申作春 National Key Laboratory of Tunable Laser Technology Harbin Institute of Technology Harbin 150001 School of Electric and Information Engineering Heilongjiang University of Science and Technology Harbin 150022 Key Laboratory of Transparent Opto-Functional Inorganic Materials Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050

A stable diode-pumped passively Q-switched Tm,Ho：YVO4 laser with Cr：ZnS saturable absorber is reported. The shortest pulse duration of -500 ns with the central wavelength of 2041 nm is obtained at the pump power of ... 详细信息

关键词： pulsed lasers RESEARCH DIODE-pumped solid state lasers THERMAL properties WAVELENGTH measurement PHYSICAL & theoretical chemistry RESONATORS

Stable single-mode operation of injection-seeded Q-switched Nd:YAG laser by sine voltage modulation

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Chinese Optics Letters 2016年第7期14卷 56-59页

作者：高永飞张俊璇臧华国朱小磊于瀛洁陈卫标 Key Laboratory of Space Laser Communication and Detection Technology Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai University University of Chinese Academy of Sciences

Based on the modified ramp and fire technique, a novel injection seeding approach with real-time resonance tracking is successfully demonstrated in a single-frequency Nd：YAG pulsed laser. Appling a high-frequency sinusoidal modulation voltage to one piezo actuator and an adjustable DC voltage to another piezo actuator for active feedbackm single-mode laser output with high-frequency stability is obtained, and the effect of the piezo hysteresis on the frequency stability can be eliminated for a laser diode pumped @switched Nd：YAG laser at a repetition rate of 400 Hz.

关键词： Actuators Frequency stability Modulation pulsed lasers Pumping (laser) Q switched lasers Q switching

The Carrier-Envelope Phase of Focused Few-Cycle Laser Pulses

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Chinese Physics Letters 2006年第1期23卷 110-112页

作者：周永恒蒋红兵龚旗煌 Department of Physics and State Key Laboratory for Mesoscopic Physics Peking University Beijing 100871

The Gouy phase shift modulates the carrier-envelope phase of a focused few-cycle laser pulse. We investigate the variations of the carrier-envelope （CE） phase of a pulsed Gaussian beam on and off the axis by the first-order approximation and numerical calculation. The CE phase undergoes a π shift from minus infinity to infinity, and it changes fastest with distance at the focus. The variation of CE phase on propagation distance is nearly independent of pulse duration At when At is greater than lO fs and the first order approximation fits this result very well. The maximum difference of CE phase between a pulse with duration of one cycle and the result of first-order approximation is 0.09.

关键词： Infinity approximation propagation distance Phase shift FIRST ORDER pulse duration laser beams Infinite Gaussian beams Phase pulsed lasers

Enhanced Three-Photon Absorption by Symmetric Twisted Intramolecular Charge Transfer

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Chinese Physics Letters 2005年第6期22卷 1394-1397页

作者：郭福全杨军张其锦明海 StructureResearchLaboratory UniversityofScienceandTechnologyofChinaHefei230026 DepartmentofPhysics UniversityofScienceandTechnologyofChinaHefei230026 DepartmentofPolymerScienceandEngineering UniversityofScienceandTechnologyofChinaHefei230026

We report on a novel organic chromophore with symmetric twisted intramolecular charge transfer (TICT) state on excitation. The properties of nonlinear transmission induced by three-photon absorption (3PA) are demonstrated pumped with nanosecond laser pulse. Large 3PA cross sections as high as the order of 10-74cm6s2 have been obtained for nanosecond and picosecond laser pulses at 1064nm from intensity-dependent transmission measurements. Similar two emissive behaviours from one-photon and three-photon excited fluorescence spectra indicate that the linear and nonlinear fluorescences share the same TICT relaxation process from the excited states. The intensity dependence of upconversion fluorescence on the incident intensity obeys the cubic law that characterizes the three-photon absorption.

关键词： COMPOUND 2-PHOTON FLUORESCENCE EXCITATION STORAGE charge transfer CENTROSYMMETRIC Photon absorption Storage Picosecond pulsed laser device absorption compounds Excitation pulsed lasers Fluorescence