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Influences of finite gain bandwidth on pulse propagation in parabolic fiber amplifiers with distributed gain profiles

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Chinese Physics B 2012年第9期21卷 345-352页

作者：赵佳生李磐陈晓东冯素娟毛庆和 anhui provincial key laboratory of photonics devices and materials Anhui Institute of Optics and Fine MechanicsChinese Academy of Sciences University of Science and Technology of China

The evolutions of the pulses propagating in decreasing and increasing gain distributed fiber amplifiers with finite gain bandwidths are investigated by simulations with the nonlinear SchrSdinger equation. The results show that the parabolic pulse propagations in both the decreasing and the increasing gain amplifiers are restricted by the finite gain bandwidth. For a given input pulse, by choosing a small initial gain coefficient and gain variation rate, the whole gain for the pulse amplification limited by the gain bandwidth may be higher, which is helpful for the enhancement of the output linearly chirped pulse energy. Compared to the decreasing gain distributed fiber amplifier, the increasing gain distributed amplifier may be more conducive to suppress the pulse spectral broadening and increase the critical amplifier length for achieving a larger output linearly chirped pulse energy.

关键词： finite gain bandwidth parabolic pulse linearly chirped pulse energy

First-principles calculation of the structural, electronic, elastic, and optical properties of sulfur-doping ε-GaSe crystal

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Chinese Physics B 2016年第8期25卷 266-273页

作者：黄昌保吴海信倪友保王振友戚鸣张春丽 anhui provincial key laboratory of Photonic devices and materials Anhui Institute of Optics and Fine MechanicsChinese Academy of Sciences

The structural,electronic,mechanical properties,and frequency-dependent refractive indexes of GaSe1-xSx（x=0,0.25,and 1） are studied by using the first-principles pseudopotential method within density functional *** calculated results demonstrate the relationships between intralayer structure and elastic modulus in GaSe1-xSx（x=0,0.25,and 1）.Doping of ε-GaSe with S strengthens the Ga-X bonds and increases its elastic moduli of C（11） and C（66）.Born effective charge analysis provides an explanation for the modification of cleavage properties about the doping of e-GaSe with *** calculated results of band gaps suggest that the distance between intralayer atom and substitution of S（Se）,rather than interlayer force,is a key factor influencing the electronic exciton energy of the layer *** calculated refractive indexes indicate that the doping of ε-GaSe with S reduces its refractive index and increases its birefringence.

关键词： S-doping GaSe first-principles linear response mechanical properties

Theoretical analysis of stack gas emission velocity measurement by optical scintillation

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Chinese Physics B 2014年第4期23卷 202-207页

作者：杨阳董凤忠倪志波庞涛曾宗泳吴边张志荣 anhui provincial key laboratory of Photonic devices and materials Anhui Institute of Optics and Fine MechanicsChinese Academy of Sciences

Theoretical analysis for an online measurement of the stack gas flow velocity based on the optical scintillation method with a structure of two parallel optical paths is performed. The causes of optical scintillation in a stack are first introduced. Then, the principle of flow velocity measurement and its mathematical expression based on cross correlation of the optical scintillation are presented. The field test results show that the flow velocity measured by the proposed technique in this article is consistent with the value tested by the Pitot tube. It verifies the effectiveness of this method. Finally, by use of the structure function of logarithmic light intensity fluctuations, the theoretical explanation of optical scintillation spec- tral characteristic in low frequency is given. The analysis of the optical scintillation spectrum provides the basis for the measurement of the stack gas flow velocity and particle concentration simultaneously.

关键词： optical scintillation cross correlation flow velocity spectrum

Simultaneous low extinction and high local field enhancement in Ag nanocubes

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Chinese Physics B 2011年第3期20卷 1-8页

作者：周飞刘晔李志远 laboratory of Optical Physics Institute of Physics Chinese Academy of Sciences anhui provincial key Lab of photonics devices and materials Anhui Institute of Optics and Fine Mechanics Chinese Academy of Sciences Hefei 230031

We theoretically investigate surface plasmon resonance properties in Au and Ag cubic nanoparticles and find a novel plasmonic mode that exhibits simultaneous low extinction and high local field enhancement properties. We analyse this mode from different aspects by looking at the distribution patterns of local field intensity, energy flux, absorption and charge density. We find that in the mode the polarized charge is highly densified in a very limited volume around the corner of the nanocube and results in very strong local field enhancement. Perturbations of the incident energy flux and light absorption are also strongly localized in this small volume of the corner region, leading to both low absorption and low scattering cross section. As a result, the extinction is low for the mode. Metal nanoparticles involving such peculiar modes may be useful for constructing nonlinear compound materials with low linear absorption and high nonlinearity.

关键词： surface plasmon resonance low extinction local field enhancement

Accuracy improvement of calibration-free laser-induced breakdown spectroscopy

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Plasma Science and Technology 2019年第3期21卷 6-15页

作者： Hongbo FU Zhibo NI Huadong WANG Junwei JIA Fengzhong DONG anhui provincial key laboratory of photonics devices and materials Anhui Institute of Optics and Fine Mechanics Chinese Academy of Sciences key laboratory of Environmental Optics & Technology Anhui Institute of Optics and Fine MechanicsChinese Academy of Sciences University of Science and Technology of China

Calibration-free laser-induced breakdown spectroscopy can overcome the matrix effect and the huge application prospects of in situ and on-line measurement, so it has been studied and applied to many analytical samples by numerous researchers since it was first proposed in ***, its accuracy is always lower than other analytical techniques and traditional quantitative analysis methods of laser-induced breakdown spectroscopy. The goal of this paper is to review the improvement of accuracy in the experimental setup and spectral analysis,especially after 2010, but not limited to it. The main contents include the accurate measurement of spectral intensity, the spatial and temporal window of local thermodynamic equilibrium and the accurate calculation of temperature and electron density. Due to the requirement of one or more standard samples, the combination of standard samples and CF-LIBS is discussed as a separate section. Finally, a simple conclusion is offered to relevant researchers who want to use CF-LIBS for quantitative analysis.

关键词： CF-LIBS quantitative analysis accuracy self-absorption local thermodynamic equilibrium

Sensitive absorption measurements of hydrogen sulfide at 1.578 μm using wavelength modulation spectroscopy

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Chinese Physics B 2015年第3期24卷 180-184页

作者：夏滑董凤忠吴边张志荣庞涛孙鹏帅崔小娟韩荦王煜 anhui provincial key laboratory of Photonic devices and materials Anhui Institute of Optics&Fine MechanicsChinese Academy of Sciences

Sensitive detection of hydrogen sulfide（H2S） has been performed by means of wavelength modulation spectroscopy（WMS） near 1.578 μm. With the scan amplitude and the stability of the background baseline taken into account, the response time is 4 s for a 0.8 L multi-pass cell with a 56.7 m effective optical path length. Moreover, the linearity has been tested in the 0–50 ppmv range. The detection limit achievable by the Allan variance is 224 ppb within 24 s under room temperature and ambient pressure conditions. This tunable diode laser absorption spectroscopy（TDLAS） system for H2 S detection has the feasibility of real-time online monitoring in many applications.

关键词： tunable diode laser spectroscopy wavelength modulation hydrogen sulfide detection low absorbance condition

Core–Shell Structure and Luminescence of SrMoO_4:Eu^(3+)(10%) Phosphors

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Journal of materials Science & Technology 2016年第12期32卷 1361-1371页

作者： Yanan Zhu Ganhong Zheng Zhenxiang Dai Lingyun Zhang Jingjing Mu anhui key laboratory of Information materials and devices School of Physics and Materials ScienceAnhui University

SrMoO4：Eu^3＋（10%） phosphors were produced via hydrothermal synthesis and *** systematically analyzed how the morphology and luminescence properties of the phosphors were affected by the synthesis conditions,including the p H of the precursor solution,stirring speed,and postsintering *** samples synthesized at p H = 8 and 9 were spindle-like rods with a core-shell *** the stirring speed increased to Vs = 150 r/min,the core-shell structure *** measurements indicated that the Sr Mo O4：Eu^3＋samples under ultraviolet radiation produced strong red emission centered at 616 *** luminescence properties were greatly affected by the p H,stirring during hydrothermal reaction,and use of *** related mechansim is discussed.

关键词： SrMoO4 Core-sheIlstructure Eu^3+-doped Luminescence

Mid-IR Dual-Wavelength Difference Frequency Generation Using Fiber Lasers as Pump and Signal Light Sources

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Chinese Physics Letters 2009年第12期26卷 153-155页

作者：蒋建常建华冯素娟毛庆和刘文清 anhui provincial key Lab of photonics devices and materials Anhui Institute of Optics and Fine Mechanics Chinese Academy of Sciences Hefei 230031

A continuous-wave mid-IR difference frequency laser source, which respectively uses an ytterbium-doped fiber laser as the pump source and a multiwavelength erbium-doped fiber laser cascaded with an erbium-doped fiber amplifier as the signal source, is demonstrated. Our experimental results show that two stable mid-IR radiation lines with a spacing of about 5.4nm may be simultaneously emitted by a suitable setting the pump and signal polarization orientations. The number of the mid-IR radiation lines is limited by the quasi-phase-matching acceptance bandwidth. By changing the PPMgLN temperature the two mid-IR radiation lines may be synchronously tuned in the mid-IR range between 3295 and 3356.3nm.

关键词： Optics quantum optics and lasers

Influences of cavity dispersion distribution on the output pulse properties of an all-normal-dispersion fiber laser

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Chinese Physics B 2015年第7期24卷 268-274页

作者：李磐时雷孙青冯素娟毛庆和 anhui provincial key laboratory of photonics devices and materials Anhui Institute of Optics and Fine MechanicsChinese Academy of Sciences Beijing Aerospace Control Instrument Research Institute Optics Division National Institute of Metrology

In this paper, the influences of the dispersion distribution in the cavity on the output pulse properties of the all-normaldispersion（ANDi） fiber laser are investigated. Our simulations show that, as the relative length of the dispersion fiber increases, the temporal width and the spectral bandwidth of the output pulse for an ANDi fiber laser with fixed total cavity dispersion or fiber length are decreased, while the pulse energy is enhanced and the compressed pulse width is *** simulation predictions have been proved by our experimental results. The reason may be that the nonlinear phase shift accumulated in the nonlinear fiber is more than that in the dispersion fiber if they have the same length.

关键词： mode-locked lasers fiber lasers dispersion nonlinearity