色散透镜系统中宽带厄米-高斯光束的焦移
作者：
谢鹏飞;彭润伍;谢海情
期刊：
激光技术 ,2019年43(3):406-410 ISSN：1001-3806
作者机构：
长沙理工大学 物理与电子科学学院,长沙,410114;[彭润伍; 谢海情; 谢鹏飞] 长沙理工大学
关键词：
激光物理;焦移;色散透镜;带宽
摘要：
为了了解带宽对厄米-高斯光束的聚焦特性和焦移的影响,采用衍射积分推导了TEM11模和TEM22模厄米-高斯光束通过受光阑限制色散透镜的传输公式,并利用数值计算对聚焦光强分布进行了研究,分析了带宽对两种模式焦移的影响。结果表明,TEM11模和TEM22模厄米-高斯光束的焦移量都会随带宽增大而增大,但两者的大小依赖相对带宽;当相对带宽小于0.25时,TEM22模焦移量大于TEM11模焦移量,然而相对带宽大于0.25时,后者会稍大于前者;带宽变化使TEM22模轴上光强主极大和次极大发生消长,从而引起轴上光强极大位置发生跃变。该研究结果对宽带厄米-高斯光束的应用具有一定的参考价值。
语种：
中文
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A polarization- and direction-independent phase-matching for third harmonic generation
作者：
Zeng, Yixuan;Tang, Zhixiang* ;Zhou, Zheng;Wang, Xuejiao;Chen, Xin;...
期刊：
Journal of Optics ,2019年21(4):045501 ISSN：2040-8978
通讯作者：
Tang, Zhixiang
作者机构：
[Zeng, Yixuan; Chen, Xin; Wang, Xuejiao; Tang, Zhixiang; Huang, Shengye; Fug, Xiquan; Zhou, Zheng] Hunan Univ, Coll Comp Sci & Elect Engn, Changsha 410082, Hunan, Peoples R China.;[Zou, Yanhong] Hunan Univ, Coll Phys & Microelect Sci, Changsha 410082, Hunan, Peoples R China.;[Peng, Runwu] Changsha Univ Sci & Technol, Dept Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Tang, Zhixiang] H;Hunan Univ, Coll Comp Sci & Elect Engn, Changsha 410082, Hunan, Peoples R China.
关键词：
Aluminum nitride;Conversion efficiency;Efficiency;Finite difference time domain method;Harmonic analysis;III-V semiconductors;Nonlinear optics;Phase matching;Photonic crystals;Polarization;Refractive index;Time domain analysis;Direction-independent;Dispersive medium;Effective refractive index;Nonlinear finite difference;Photonic crystal (PhCs);Propagation direction;Propagation lengths;Two dimensional square lattice;Harmonic generation
摘要：
We proposed a nearly perfect phase-matching for third harmonic generation (THG) in photonic crystals (PhCs), which is independent of the polarization and propagation direction of the fundamental wave. Taking an AlN-like Kerr medium as an example, equal effective refractive indices of the fundamental and the triple frequencies were achieved for both the TM and TE modes simultaneously by fabricating this dispersive medium into a two-dimensional square-lattice PhC. Furthermore, the THG conversion efficiency were numerically calculated by using the nonlinear finite-difference time-domain method to simulate Gaussian pulses with TM and TE polarizations propagating along the high-symmetry directions of the PhC (ΓX and ΓM), respectively. The simulation results show that all THG conversion efficiencies increase with the propagation length like a parabola regardless of the polarization and the propagation direction of the incident fundamental wave, indicating a nearly perfect phase matching. © 2019 IOP Publishing Ltd.
语种：
英文
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Reversing the sign of the effective nonlinear coefficient of a nearly isotropic Kerr photonic crystal via the local-field effect
作者：
Zeng, Yixuan;Tang, Zhixiang* ;Wang, Xuejiao;Chen, Xin;Fu, Xiquan;...
期刊：
Optical Materials Express ,2018年8(8):2256-2263 ISSN：2159-3930
通讯作者：
Tang, Zhixiang
作者机构：
[Zeng, Yixuan; Chen, Xin; Wang, Xuejiao; Tang, Zhixiang; Huang, Shengye; Fu, Xiquan] Hunan Univ, Coll Comp Sci & Elect Engn, Changsha 410082, Hunan, Peoples R China.;[Zou, Yanhong] Hunan Univ, Sch Phys & Elect, Changsha 410082, Hunan, Peoples R China.;[Peng, Runwu] Changsha Univ Sci & Technol, Dept Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Tang, Zhixiang] H;Hunan Univ, Coll Comp Sci & Elect Engn, Changsha 410082, Hunan, Peoples R China.
关键词：
Finite difference time domain method;High power lasers;Polarization;Effective nonlinear coefficient;Local-field effects;Nonlinear coefficient;Nonlinear propagation;Operating frequency;Self-focusing;Sign reversal;Spectral broadening;Photonic crystals
摘要：
The sign of the Kerr nonlinear coefficient, which determines the nonlinear propagation characteristics of high-power lasers, is usually only sensitive to the operating frequency. Here, we report a method to reverse the sign according to the polarization of the input beam. The sign reversal is realized in the first band of a two-dimensional Kerr photonic crystal (PhC) by using local-field effects. By appropriately adjusting the unit cell, we find that the effective nonlinear coefficient of the PhC is negative for the TM mode while positive for the TE mode. Using the FDTD method, polarization-dependent spectral broadening and narrowing, self-focusing and defocusing are demonstrated in the nearly isotropic PhC. © 2018 Optical Society of America.
语种：
英文
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矩形谱宽带激光中带宽诱导的焦开关现象
作者：
张笔雨;彭润伍;张伟
期刊：
激光技术 ,2017年41(1):138-140 ISSN：1001-3806
作者机构：
[张笔雨; 彭润伍; 张伟] 长沙理工大学物理与电子科学学院, 长沙, 410114
关键词：
激光光学;焦开关;双焦系统;带宽
摘要：
为了研究频带宽度对激光光束传输和激光应用产生的影响,采用衍射积分推导了矩形谱宽带激光通过双焦色散透镜后的传输公式,利用数值计算研究了矩形谱宽带激光带宽诱导的焦开关现象,分析得到带宽对光强分布和焦开关的影响。结果表明,带宽是影响光强分布和焦开关形成的重要因素;带宽变化会导致光强分布中光强主极大从一个位置跃变到另一个位置,从而形成焦开关现象。该研究结果有助于进一步推动宽频带激光的应用。
语种：
中文
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光电信息类专业校企合作人才培养示范基地建设探索
作者：
彭润伍;唐俊龙;谢海情
期刊：
教育教学论坛 ,2017年(28):40-42 ISSN：1674-9324
作者机构：
长沙理工大学 物理与电子科学学院,湖南 长沙,410114;[彭润伍; 谢海情; 唐俊龙] 长沙理工大学
关键词：
校企合作;人才培养;创新能力;示范基地
摘要：
校企合作人才培养模式是适应经济社会发展和产业转型升级的教育模式，对于推动学生专业实践能力和创新创业素质的培养有重要意义。本文以长沙理工大学与湖南明和光电设备有限公司光电信息类专业校企合作人才培养示范基地建设为例，研究和探索了校企合作培养人才的新模式和新机制，介绍了基地建社内容和提高学生能力的具体途径和方法，改革研究成果对于其他专业或其他高校同类专业具有借鉴作用。
语种：
中文
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Tuning subwavelength-structured focus in the hyperbolic metamaterials
作者：
Pan, Rong;Tang, Zhixiang* ;Pan, Jin;Peng, Runwu
期刊：
Proceedings of SPIE - The International Society for Optical Engineering ,2016年10154:101541U ISSN：0277-786X
通讯作者：
Tang, Zhixiang
作者机构：
[Tang, Zhixiang; Pan, Jin; Pan, Rong] Hunan Univ, Coll Comp Sci & Elect Engn, Changsha 410082, Hunan, Peoples R China.;[Peng, Runwu] Changsha Univ Sci & Technol, Dept Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Tang, Zhixiang] H;Hunan Univ, Coll Comp Sci & Elect Engn, Changsha 410082, Hunan, Peoples R China.
会议名称：
International Symposium on Advanced Optical Design and Manufacturing Technologies / International Symposium on Astronomical Telescope and Instrumentation
会议时间：
MAY 09-11, 2016
会议地点：
Beijing, PEOPLES R CHINA
会议主办单位：
[Pan, Rong;Tang, Zhixiang;Pan, Jin] Hunan Univ, Coll Comp Sci & Elect Engn, Changsha 410082, Hunan, Peoples R China.^[Peng, Runwu] Changsha Univ Sci & Technol, Dept Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
会议论文集名称：
Proceedings of SPIE
关键词：
Multilayered structures;Subwavelength imaging;Surface plasmons
摘要：
In this paper, we have systematically investigated light propagating in the hyperbolic metamaterials (HMMs) covered by a subwavelength grating. Based on the equal-frequency contour analyses, light in the HMM is predicted to propagate along a defined direction because of its hyperbolic dispersion, which is similar to the self-collimating effects in photonic crystals. By using the finite-difference time-domain, numerical simulations demonstrate a subwavelength bright spot at the intersection of the adjacent directional beams. Different from the images in homogeneous media, the magnetic fields and electric fields at the spot are layered, especially for the electric fields Ez that is polarized to the propagating direction, i.e., the layer normal direction. Moreover, the Ez is hollow in the layer plane and is stronger than the other electric field component Ex. Therefore, the whole electric field is structured and its pattern can be tuned by the HMM's effective anisotropic electromagnetic parameters. Our results may be useful for generating subwavelength structured light. ©2016 SPIE.
语种：
英文
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Analysis of nonlinear effects caused by TE waves propagating in two-dimensional Kerr photonic crystals
作者：
Pan, Jin;Tang, Zhixiang* ;Pan, Rong;Zhou, Ketao;Peng, Runwu
期刊：
Proceedings of SPIE - The International Society for Optical Engineering ,2016年10155:101552S ISSN：0277-786X
通讯作者：
Tang, Zhixiang
作者机构：
[Zhou, Ketao; Tang, Zhixiang; Pan, Jin; Pan, Rong] Hunan Univ, Coll Comp Sci & Elect Engn, Changsha 410082, Hunan, Peoples R China.;[Peng, Runwu] Changsha Univ Sci & Technol, Dept Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Tang, Zhixiang] H;Hunan Univ, Coll Comp Sci & Elect Engn, Changsha 410082, Hunan, Peoples R China.
会议名称：
International Symposium on Optical Measurement Technology and Instrumentation
会议时间：
MAY 09-11, 2016
会议地点：
Beijing, PEOPLES R CHINA
会议主办单位：
[Pan, Jin;Tang, Zhixiang;Pan, Rong;Zhou, Ketao] Hunan Univ, Coll Comp Sci & Elect Engn, Changsha 410082, Hunan, Peoples R China.^[Peng, Runwu] Changsha Univ Sci & Technol, Dept Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
会议论文集名称：
Proceedings of SPIE
关键词：
Field localization;Kerr effect;Photonic crystal;Slow light effects
摘要：
As the two main ways to enhance nonlinearity in nano-structured materials, field localization and slow light effects could cooperate to exert influence on nonlinear effect enhancement together. By considering the co-influence of them, we can make use of a field averaging method to calculate the effective nonlinear refractive index coefficient (n<inf>2</inf>) of Kerr photonic crystals (PhCs). In this paper, we treat the propagation of TE waves in Kerr PhCs in detail as a complementary to TM waves and calculate the effective n<inf>2</inf>in the first band. Although TM waves and TE waves may cause different nonlinear effects in two-dimensional Kerr PhCs, it proves that our theoretical calculating method also works well for TE waves. ©2016 SPIE.
语种：
英文
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Variation of focal switch with spectrum of a broadband laser
作者：
Zhang, Biyu;Peng, Runwu* ;Xie, Haiqing;Zhang, Wei
期刊：
Optics Communications ,2016年366:271-274 ISSN：0030-4018
通讯作者：
Peng, Runwu
作者机构：
[Zhang, Biyu; Zhang, Wei; Xie, Haiqing; Peng, Runwu] Changsha Univ Sci & Technol, Dept Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Peng, Runwu] C;Changsha Univ Sci & Technol, Dept Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
关键词：
Bandwidth;Absolute values;Broad-band lasers;Central frequency;Central wavelength;Focal switch;Maximum intensities;Numerical results;Spectrum;Dispersion (waves)
摘要：
Effects of the spectrum on focal switch of a broadband laser in a dispersion dual-focus system are presented in this paper. The numerical results show that the two maximum intensities of the broadband laser on the z-axis vary when the central frequency of the broadband laser shifts and the spectrum shape changes, and the variations affect the generation of the focal switch. It is also found that difference of the two maximum intensities tends to increase when the absolute value of central wavelength increases. According to the results in this paper, the generation of the focal switch can be controlled by choosing the shift of the central frequency, the bandwidth, the distance between the two lenses, and the spectrum shape of the broadband laser. (C) 2015 Elsevier B.V. All rights reserved.
语种：
英文
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带宽对余弦高斯宽带激光强度分布的影响
作者：
张伟;袁娜;汪娟;陈维;彭润伍
期刊：
光学与光电技术 ,2015年13(6):27 ISSN：1672-3392
作者机构：
长沙理工大学物理与电子科学学院,湖南长沙,410114;[袁娜; 彭润伍; 陈维; 汪娟; 张伟] 长沙理工大学
关键词：
带宽;聚焦;强度分布;窄化效应
摘要：
基于衍射积分推导了矩形光谱的余弦高斯空间模式宽带激光通过薄透镜的传输公式,研究了激光通过薄透镜后的横向强度分布。通过数值计算比较分析了不同带宽时的强度分布波形变化。计算结果表明,在菲涅耳数较小的情况下,矩形光谱的余弦高斯空间模式宽带激光通过薄透镜后横向强度随带宽增大而变窄。但随着菲涅耳数增大,带宽对强度分布的影响减小。研究结果对宽带激光传输特性的深入研究和宽带激光的应用具有指导意义。
语种：
中文
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集成电路设计专业课程体系改革与实践
作者：
谢海情;唐立军;唐俊龙;文勇军;彭润伍;...
期刊：
教育教学论坛 ,2015年(34):76-77 ISSN：1674-9324
作者机构：
长沙理工大学 物理与电子科学学院,湖南 长沙,410004;[唐立军; 勇军; 周晓萍; 彭润伍; 谢海情; 唐俊龙] 长沙理工大学
关键词：
课程体系改革;教学内容优化;集成电路设计
摘要：
专业课程体系是实现人才培养目标的重要保障。为实现我校集成电路设计专业人才培养目标,根据已提出的创新型集成电路设计人才培养模式,结合我校目前人才培养现状与特征,改革优化集成电路设计专业课程体系。提出"4+3+2"专业课程体系,并优化集成电路设计专业课程的授课内容。
语种：
中文
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Intensity Distributions of a Supercontinuum Laser in an Apertured Dispersion Lens
作者：
Yuan Na;Zhang Wei;Wang Juan;Chen Wei;Peng Run-Wu*
期刊：
中国物理快报：英文版 ,2015年32(3):034201 ISSN：0256-307X
通讯作者：
Peng Run-Wu
作者机构：
[Yuan Na; Zhang Wei; Chen Wei; Peng Run-Wu; Wang Juan] Changsha Univ Sci & Technol, Dept Phys & Elect Sci, Changsha 410114, Peoples R China.
通讯机构：
[Peng Run-Wu] C;Changsha Univ Sci & Technol, Dept Phys & Elect Sci, Changsha 410114, Peoples R China.
关键词：
连续激光器;强度分布;镜片;色散;多孔;截断参数;中心波长;带宽和
摘要：
We present intensity distributions of a supercontinuum laser passing through an apertured dispersion lens and find focal shift effects generated. The results show that, apart from the conventional negative focal shift, a positive focal shift also appears in the supercontinuum laser. The maximum intensity of the supercontinuum laser shifts toward the lens when the truncated parameter is small. However, it exceeds the focus of the central wavelength and a positive focal shift appears in the supercontinuum laser with large truncated parameter. Both of the maximum intensities shift away from the focus when the bandwidth of the supercontinuum laser increases, while the shift direction is opposite. No focal shift appears when the bandwidth and the truncated parameter satisfy some conditions.
语种：
英文
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Focal switch of broadband laser in a dispersion dual-focus system
作者：
Peng, Runwu* ;Zhai, Fanghua;Zhang, Biyu;Li, Le;Yuan, Na;...
期刊：
Optics Communications ,2015年352:14-18 ISSN：0030-4018
通讯作者：
Peng, Runwu
作者机构：
[Zhai, Fanghua; Zhang, Biyu; Li, Le; Zhang, Wei; Yuan, Na; Peng, Runwu] Changsha Univ Sci & Technol, Dept Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Peng, Runwu] C;Changsha Univ Sci & Technol, Dept Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
关键词：
Dispersion (waves);Dispersions;Broad-band lasers;Dual focus;Focal switch;Fresnel number;Intensity distribution;Maximum intensities;Narrow bandwidth;Spectrum;Bandwidth
摘要：
Focal switch effect of broadband laser in a dispersion dual-focus system with large Fresnel number is reported in this paper. Influences of the bandwidth on the intensity distributions and focal switch are illustrated by numerical examples. The results indicate that the bandwidth brings on the variations of two maximum intensities on the axis and thus results in the generation of focal switch. Fresnel number and the distance between two lenses also have influence on the focal switch. The bandwidth needed for the generation of the focal switch decreases when the Fresnel number and the distance between the two lenses increase. Narrow bandwidth can induce the focal switch in the system with large Fresnel number but the bandwidth needed for the generation of the focal switch increases rapidly when the Fresnel number decreases. © 2015 Elsevier B.V.
语种：
英文
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914nm LD泵浦的基模振荡器设计
作者：
肖庆华;林家娟;刘强;胡钦;文蓉江;...
期刊：
光学与光电技术 ,2015年13(5):38 ISSN：1672-3392
作者机构：
长沙理工大学物理与电子科学学院,湖南长沙,410114;[林家娟; 肖庆华; 刘强; 彭润伍; 胡钦; 文蓉江] 长沙理工大学
关键词：
斯托克斯因子;振荡器;模参数;ABCD定律
摘要：
为建立一个高效率的基模振荡器模型,采用谐振腔理论和ABCD定律计算分析了热透镜对腔内模式的影响,研究了不同泵浦源对斯托克斯因子的影响。研究结果表明,在热透镜焦距300~350 mm范围内腔模变化较小,采用914 nm泵浦源可以提高斯托克斯因子从而提高振荡器效率。设计的基模振荡器在泵浦功率为50 W时,可得到34.7 W的激光输出,效率达到69.4%。 In order to setup a model of a fundamental mode oscillator with high efficiency, effects of the thermal lens on the cave mode are analyzed by using the oscillator theory and ABCD laws and influence of pump source on the Stokes factor is also studied. The results indicate that changes of the cave mode is small when the thermal focus is in the range of 300~350 mm. The Stokes factor increases by using 914 nm pump power and thus the efficiency of the oscillator can be enhanced. The output power of the designed fundamental mode oscillator is 34.7 W with efficiency of 69.4% when pump power is 50 W.
语种：
中文
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Influence of aperture and bandwidth on fields of polychromatic laser
作者：
Peng, Runwu* ;Tang, Lijun;Li, Yajie;Wu, Guanhong;Shi, Jian
期刊：
Optik ,2013年124(2):122-125 ISSN：0030-4026
通讯作者：
Peng, Runwu
作者机构：
[Tang, Lijun; Li, Yajie; Shi, Jian; Peng, Runwu; Wu, Guanhong] Changsha Univ Sci & Technol, Dept Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Peng, Runwu] C;Changsha Univ Sci & Technol, Dept Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
关键词：
Hard-edged aperture;Numerical calculation;Peak intensity;Spreading effects;Lasers;Bandwidth
摘要：
Fields of polychromatic laser passing through a hard edged aperture is derived and the influence of aperture and bandwidth on the fields is investigated. Transverse intensity of the polychromatic laser through aperture with different width has been illustrated by numerical calculation. It is shown that the spreading effect presents more obvious when the aperture width decreases and the bandwidth increases. Position of intensity peak increases when bandwidth increases but it increase rapidly from bandwidth 0 to 0.2 and slowly exceed 0.2. A physical explanation for the phenomenon that the position of peak intensity varies with bandwidth is also given. © 2011 Elsevier GmbH. All rights reserved.
语种：
英文
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带宽对平顶高斯宽带激光传输特性的影响
作者：
彭润伍;李乐;李亚捷;谢海情;唐立军
期刊：
强激光与粒子束 ,2013年25(8):1935-1938 ISSN：1001-4322
通讯作者：
Peng, R.(pengrunwu@163.com)
作者机构：
[李乐; 谢海情; 彭润伍; 李亚捷; 唐立军] Department of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114, China
通讯机构：
Department of Physics and Electronic Science, Changsha University of Science and Technology, China
关键词：
激光物理;频带宽度;时空耦合;窄化效应;扩展效应
摘要：
研究了横向分布为平顶高斯模式的宽带激光在自由空间的传输特性，分析了频带宽度对其强度分布的影响。首先推导了平顶高斯模式宽带激光的每一频率分量在自由空间的传输公式，然后将频率域的传输公式通过傅里叶变换得到时间域的传输公式。基于推导的公式通过数值算例给出了不同频带宽度激光光束的强度分布结果，详细分析了空间模式的变化和时空耦合现象。研究结果表明：随着传输距离增大，平顶高斯空间模式趋于高斯分布。同时随着带宽增大，平顶高斯模式宽带激光表现出更强的时空耦合现象，并导致其空间横向分布发生明显变化。变化的主要特征为波前的强度分布随带宽增大而变窄，波后的强度分布则随带宽增大而远离轴中心向外扩展。
语种：
中文
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平顶高斯模式宽带激光通过光阑的光强分布
作者：
彭润伍;李乐;李亚捷;谢海情;唐立军
期刊：
激光技术 ,2013年37(6):829-832 ISSN：1001-3806
作者机构：
[彭润伍; 李乐; 李亚捷; 谢海情; 唐立军] 长沙理工大学物理与电子科学学院
关键词：
激光光学;宽带激光;衍射积分;硬边光阑;窄化现象
摘要：
为了研究横向分布为平顶高斯模式的宽带激光通过硬边光阑系统的光强分布特性，采用衍射积分公式推导了平顶高斯模式宽带激光的每一频率分量在光阑系统中的传输公式，再通过傅里叶变换得到时间域的传输公式，详细分析了光阑和频带宽度对强度分布的影响。结果表明，近场光强在截断参量较大时，仍保持一定的平顶分布特性，但是随带宽的增加强度分布变窄；截断参量较小时强度呈高斯分布，并且带宽的变化对强度分布没有太大影响；然而在远场时截断参量较小情况下的光强分布也明显表现出随带宽增加而变窄的现象，但随着截断参量增大，这一变化趋势变缓。这些结果对平顶高斯模式宽带激光的应用具有重要参考价值。
语种：
中文
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Positive and negative focal shifts of an apertured supercontinuum laser with rectangular spectrum
作者：
Peng, Runwu* ;Li, Le;Li, Yajie;Xie, Haiqing;Dou, Liuming
期刊：
Optics Communications ,2013年298-299:34-36 ISSN：0030-4018
通讯作者：
Peng, Runwu
作者机构：
[Li, Yajie; Dou, Liuming; Li, Le; Xie, Haiqing; Peng, Runwu] Changsha Univ Sci & Technol, Dept Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Peng, Runwu] C;Changsha Univ Sci & Technol, Dept Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
关键词：
Central wavelength;Focal shifts;Focusing system;Maximum intensities;Rectangular spectrum;Shift directions;Super continuum;Supercontinuum laser;Optics;Physics;Focusing
摘要：
In this paper, diffraction of the supercontinuum beam from aperture and lens are described for the first time. We study the positive and negative focal shift effects of the supercontinuum laser on focusing system in detail. It is found that, apart from the conventional negative focal shift, the positive focal shift is also generated in the supercontinuum laser. The maximum intensity of the focused supercontinuum laser is shifted toward the lens with small truncated parameter. When the truncated parameter is large, however, the maximum intensity exceeded the focus of the central wavelength and the positive focal shift appears. The results also show that the maximum intensities are shifted away from the focus when the bandwidth of the supercontinuum laser increases in the two cases, but the shift direction is opposite. © 2013 Elsevier B.V. All rights reserved.
语种：
英文
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Effect of spectrum property on a focused supercontinuum laser
作者：
Peng, Runwu* ;Li, Le;Li, Yajie;Tang, Long;Xie, Haiqing;...
期刊：
Optics Communications ,2013年309:26-29 ISSN：0030-4018
通讯作者：
Peng, Runwu
作者机构：
[Li, Yajie; Tang, Long; Dou, Liuming; Li, Le; Xie, Haiqing; Peng, Runwu] Changsha Univ Sci & Technol, Dept Phys & Elect Sci, Changsha 410114, Peoples R China.
通讯机构：
[Peng, Runwu] C;Changsha Univ Sci & Technol, Dept Phys & Elect Sci, Changsha 410114, Peoples R China.
关键词：
Center wavelength;Focal shifts;Intensity distribution;Numerical calculation;Spectrum;Spectrum properties;Super continuum;Supercontinuum laser;Bandwidth;Wavelength
摘要：
Fields of a focused supercontinuum laser with different center wavelength are studied near the focus in this paper. Effects of the spectrum property on the intensity distributions of the laser are analyzed in detail by numerical calculations. The results indicate that the maximum intensity is shifted toward the lens as the center wavelength decreases and it is deviated from the lens as the center wavelength shift to long wavelength. Influence of the center wavelength on the shift of the maximum intensity is smaller in the laser with broader bandwidth. Determined by the center wavelength, the focused supercontinuum laser presents positive focal shift or negative focal shift in the system with any truncated parameter. If appropriate center wavelength and bandwidth are chosen, the focal shift of the supercontinuum laser passing through a dispersive lens can be eliminated. © 2013 Elsevier B.V.
语种：
英文
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Intensity profile of chirped polychromatic laser in an apertured system
作者：
Peng, Runwu* ;Li, Yajie;Wu, Guanhong;Tang, Lijun;Shi, Jian
期刊：
OPTICS AND LASER TECHNOLOGY ,2012年44(5):1277-1280 ISSN：0030-3992
通讯作者：
Peng, Runwu
作者机构：
[Li, Yajie; Tang, Lijun; Shi, Jian; Peng, Runwu; Wu, Guanhong] Changsha Univ Sci & Technol, Dept Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Peng, Runwu] C;Changsha Univ Sci & Technol, Dept Phys & Elect Sci, Changsha 410114, Hunan, Peoples R China.
关键词：
Aperture system;Chirp parameter;Intensity distribution;Intensity profiles;Local time;Numerical calculation;Spreading effects;Electrical engineering;Magnetic materials;Wavefronts
摘要：
Propagation expression of chirped polychromatic laser in an aperture system is deduced in our investigation. Influences of the chirp parameter and the aperture width on the intensity profile of the chirped polychromatic laser are studied and illustrated by numerical calculation. The results showed that intensity of the wave rear presents spreading effect but that of the wave front presents narrowing effect. Namely, the intensity distribution spreads with decreasing the aperture width and increasing the chirp parameter in the wave rear whereas it tends to concentrate with increasing the chirp parameter in the wave front. A physical explanation based on a simplified representation indicated that the influence of the chirp parameter on the intensity was determined not only by its quantity but also by the sign of the local time. © 2012 Elsevier Ltd. All rights reserved.
语种：
英文
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带宽对平顶高斯模式宽带激光的传输特性影响研究
作者：
彭润伍;李亚捷;唐立军
作者机构：
[彭润伍; 李亚捷; 唐立军] 长沙理工大学物理与电子科学学院,长沙410114
会议名称：
第二十届全国激光学术会议
会议时间：
2012-10-18
会议地点：
成都
会议主办单位：
中国电子学会;中国光学学会;中国工程院信息与电子工程学部
会议论文集名称：
第二十届全国激光学术会议论文集
关键词：
频带宽度;时空耦合;窄化现象;扩展现象
摘要：
研究了具有平顶高斯模式横向分布的宽带激光在自由空间的传输特性，分析了频带宽度对其强度分布的影响。首先推导了平顶高斯模式宽带激光的每一频率分量在自由空间的传输公式，然后从频率域的传输公式通过傅里叶变换得到时间域的传输公式。基于推导的公式通过数值计算例给出了不同频带宽度激光光束的强度分布结果，详细分析了空间模式的变化和时空耦合现象。研究结果表明，随着传输距离增大，平顶高斯空间模式趋于高斯分布。同时随着带宽增大，平顶高斯模式宽带激光表现出更强的时空耦合现象，并导致其空间横向分布发生明显变化。变化的主要特征为波前的强度分布随带宽增大而变窄，波后的强度分布则随带宽增大而远离轴中心向外扩展。
语种：
中文
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