Vertical－cavity Surface－emitting Lasers Fabricated Twice by Implantation Using TungstenWireasMaskandZincDiffusion

Ｖｅｒｔｉｃａｌ－ｃａｖｉｔｙＳｕｒｆａｃｅ－ｅｍｉｔｔｉｎｇＬａｓｅｒｓＦａｂｒｉｃａｔｅｄＴｗｉｃｅｂｙＩｍｐｌａｎｔａｔｉｏｎＵｓｉｎｇＴｕｎｇｓｔｅｎＷｉｒｅａｓＭａｓｋａｎｄＺｉｎｃＤｉｆｆｕｓｉｏｎ￥ＪＩＡＮＧＸｉｕｙｉｎｇ；ＤＵＧｕｏｔ...     

Fundamental Soliton Compression due to Induced－phase－modulation in the Regime of Normal Group－velocity Dispersion

ＦｕｎｄａｍｅｎｔａｌＳｏｌｉｔｏｎＣｏｍｐｒｅｓｓｉｏｎｄｕｅｔｏＩｎｄｕｃｅｄ－ｐｈａｓｅ－ｍｏｄｕｌａｔｉｏｎｉｎｔｈｅＲｅｇｉｍｅｏｆＮｏｒｍａｌＧｒｏｕｐ－ｖｅｌｏｃｉｔｙＤｉｓｐｅｒｓｉｏｎ￥ＸＵＷｅｎｃｈｅｎｇ；ＬＩＵＪｕｎｍｉｎ；ＬＩ...     

Theoretical Study of the Second－order Nonlinear Generation in Glass with Crystallization

ＴｈｅｏｒｅｔｉｃａｌＳｔｕｄｙｏｆｔｈｅＳｅｃｏｎｄ－ｏｒｄｅｒＮｏｎｌｉｎｅａｒＧｅｎｅｒａｔｉｏｎｉｎＧｌａｓｓｗｉｔｈＣｒｙｓｔａｌｌｉｚａｔｉｏｎＨＡＮＪｕｇｕａｎｇ；ＧＡＯＷｅｎｙａｎ；ＪＩＡＮＧＺｈｏｎｇｈｏｎｇ（ＳｈａｎｇｈａｉＩｎｓ...     

Achievement of soft－X－ray laser with nearly saturated intensity and minimum divergence angle～1 mrad

Ａｃｈｉｅｖｅｍｅｎｔ ｏｆ ｓｏｆｔ－Ｘ－ｒａｙ ｌａｓｅｒ ｗｉｔｈ ｎｅａｒｌｙ ｓａｔｕｒａｔｅｄ ｉｎｔｅｎｓｉｔｙ ａｎｄ ｍｉｎｉｍｕｍ ｄｉｖｅｒｇｅｎｃｅ ａｎｇｌｅ～１ｍｒａｄ￥ＷＡＮＧＳｈｉｊｉ；ＧＵＹｕａｎ；ＺＨＯＵＧｕａｎｌ...     

Suppression of Interference Speckles in the Uniform Line Focus System of Segmented Wedge Array Using Phase－disturbed Plate

ＳｕｐｐｒｅｓｓｉｏｎｏｆＩｎｔｅｒｆｅｒｅｎｃｅＳｐｅｃｋｌｅｓｉｎｔｈｅＵｎｉｆｏｒｍＬｉｎｅＦｏｃｕｓＳｙｓｔｅｍｏｆＳｅｇｍｅｎｔｅｄＷｅｄｇｅＡｒｒａｙＵｓｉｎｇＰｈａｓｅ－ｄｉｓｔｕｒｂｅｄＰｌａｔｅ￥ＬＩＵＺｈｏｎｇｙｏｎｇ；ＺＨＥＮＧ...     

A New Fourier Iterative Algorithm for the Design of Phase－only Diffractive Optical Element Used in Laser Beam Shaping

ＡＮｅｗＦｏｕｒｉｅｒＩｔｅｒａｔｉｖｅＡｌｇｏｒｉｔｈｍｆｏｒｔｈｅＤｅｓｉｇｎｏｆＰｈａｓｅ－ｏｎｌｙＤｉｆｆｒａｃｔｉｖｅＯｐｔｉｃａｌＥｌｅｍｅｎｔＵｓｅｄｉｎＬａｓｅｒＢｅａｍＳｈａｐｉｎｇＳＡＮＧＴａｏ；ＬＩＡＯＪｉａｎｇｈｏｎｇ；ＬＵＺ...     

Unexpected Population Inversion in a Λ-type Medium

ＵｎｅｘｐｅｃｔｅｄＰｏｐｕｌａｔｉｏｎＩｎｖｅｒｓｉｏｎｉｎａΛ－ｔｙｐｅＭｅｄｉｕｍ￥ＧＯＮＧＳｈａｎｇｑｉｎｇ；ＤＵＳｉｄｅ；ＸＵＺｈｉｚｈａｎ（ＳｈａｎｇｈａｉＩｎｓｔｉｔｕｔｅｏｆＯｐｔｉｃｓａｎｄＦｉｎｅＭｅｃｈａｎｉｃｓ，Ｃｈｉｎｅｓｅ...     

Stimulated Brillouin scattering（SBS） excited with a phase－modulated pump laser

Ｓｔｉｍｕｌａｔｅｄ Ｂｒｉｌｌｏｕｉｎ ｓｃａｔｔｅｒｉｎｇ（ＳＢＳ） ｅｘｃｉｔｅｄ ｗｉｔｈ ａ ｐｈａｓｅ－ｍｏｄｕｌａｔｅｄ ｐｕｍｐ ｌａｓｅｒ￥ＷＥＮＧｕｏｊｕｎ；ＱＩＡＮＬｉｅｊｉａ；ＬＵＪｕｎｘｉａｏ；ＦＡＮＤｉａｎｙｕａｎ；ＤＥＮ...     

Two－Side Electron Beam Pumping System For Hundred－Joule－Level KrF Excimer Laser

Ｔｗｏ－ＳｉｄｅＥｌｅｃｔｒｏｎＢｅａｍＰｕｍｐｉｎｇＳｙｓｔｅｍＦｏｒＨｕｎｄｒｅｄ－Ｊｏｕｌｅ－ＬｅｖｅｌＫｒＦＥｘｃｉｍｅｒＬａｓｅｒ￥ＭＡＷｅｉｙｉ；ＳＨＡＮＹｕｓｈｅｎｇ；ＺＨＯＵＫｕｎｇｏｎｇ；ＷＡＮＧＹｏｕｔｉａｎ；ＺＨＡＮＧＤｏｎｇ；...     

Generation of 2－10ns Excimer Laser Pulse by Optical Synchronizing Wave－clipping

Ｇｅｎｅｒａｔｉｏｎｏｆ２－１０ｎｓＥｘｃｉｍｅｒＬａｓｅｒＰｕｌｓｅｂｙＯｐｔｉｃａｌＳｙｎｃｈｒｏｎｉｚｉｎｇＷａｖｅ－ｃｌｉｐｐｉｎｇＸＩＡＮＧＳｈｉｑｉｎｇ；ＬＯＵＱｉｈｏｎｇ；ＤＯＮＧＪｉｎｇｘｉｎｇ；ＭＡＮＧＹａｎｐｉｎｇ；ＷＥＩＹｕｎｒ...     

飞秒激光在光子晶体光纤中产生超连续光谱机制的实验研究

报道了利用零色散在780nm处的光子晶体光纤与纳焦耳量级的飞秒激光脉冲相互作用的实验结果.实验使用35fs，中心波长810—840nm，单脉冲能量可达14nJ的飞秒激光光源获得了超过一个倍频程的平坦超连续光谱（500—1100nm）.在不同功率、不同中心波长、不同啁啾和有无直流成分的多种飞秒脉冲激光的条件下，研究了超连续光谱的产生情况.并对一系列现象进行了对比，分析了超连续光谱产生的机制. 关键词： 光子晶体光纤 飞秒脉冲激光 超连续光谱     

飞秒激光在双折射微结构光纤中模式控制的四波混频效应的实验研究

利用飞秒激光脉冲在长度为10cm，包层具有大空气比的双折射微结构光纤中通过高阶模相位 匹配的四波混频获得了波长可调谐的反斯托克斯波.实验中脉冲宽度为35fs，中心波长820nm ，单脉冲能量4nJ的飞秒激光脉冲耦合到长轴直径为5μm，短轴为46μm的双折射微结构光 纤中.在高阶模传输情况下，通过调制耦合光的偏振方向，获得了具有不同中心波长的反斯 托克斯波.通过对比分析，讨论了输入光的偏振态对双折射微结构光纤中高阶模式下四波混 频效应的影响情况.理论计算分析很好的解释了实验结果. 关键词： 微结构光纤 飞秒脉冲激光 四波混频     

THz generation via optical rectification with ultrashort laser pulse focused to a line

We report on efficient THz pulse generation via optical rectification with femtosecond laser pulses focused to a line by a cylindrical lens. This configuration provides phase-matched conditions in the superluminal regime. 35 pJ THz pulses have been generated with this technique in a stoichiometric LiNbO₃ crystal pumped by 2 μJ femtosecond laser pulses at room temperature. An unusual superquadratic rise of the THz pulse energy with the laser pulse energy has been observed at high laser energies. This extraordinary energy dependence of the THz generation efficiency is explained by self-focusing of the laser beam in the crystal. Z-scan measurements and comparison of the THz pulse spectra created with laser pulses having different energies confirm this interpretation.     

在固体透明材料中利用级联四波混频方法获得宽带多色飞秒激光脉冲的研究

飞秒激光光谱学实验研究的深入与拓展对飞秒激光脉冲的要求也越来越高.比如多色抽运探测实验需要同时用到多个不同频率的超短飞秒激光脉冲.本文设计了一个更加简单紧凑的实验装置,对两束不同中心频率的入射光引入相反啁啾,在厚度为0.5 mm的CaF2晶体中利用级联四波混频获得了光谱半高全宽近100nm,支持傅里叶转换极限脉宽小于10 fs的多色飞秒激光脉冲.这一结果将为拓展飞秒激光光谱学研究和应用发挥重要作用.     

Talbot effect of a high-density grating under femtosecond laser illumination

The Talbot effect of a high-density grating under femtosecond laser illumination is analyzed with rigorous electromagnetic theory which is based on the Fourier decomposition and the rigorous coupled-wave analysis (RCWA). Numerical simulations show that the contrast of the Talbot images steadily decreases as the transmitted femtosecond laser pulses propagate forward and with wider spectrum width of the femtosecond laser pulses. The Talbot images of high-density gratings have much higher sensitivity of the spectrum widths of the incident laser pulses than those of the traditional low-density gratings. In experiments, the spectrums and the pulse widths of the incident pulses are measured with a frequency-resolved optical grating (FROG) apparatus. The Talbot images are detected by using a Talbot scanning near-field optical microscopy (Talbot-SNOM) technique, which are in coincidence with the numerical simulations. This effect should be useful for developing new femtosecond laser techniques and devices.     

Numerical modeling and theoretical analysis of femtosecond laser tweezers

Optical trapping (also called optical tweezers) is a widespread technique, with a large number of applications in biology and other fields. Taking femtosecond laser pulses as a sampling of CW light, we theoretically demonstrate the feasibility of femtosecond laser tweezers and present the formulae of the induced forces which femtosecond laser pulses exert on micrometer-sized spheres. We also demonstrate the stability condition for femtosecond laser tweezers. As an example, we present the numerical results for a sphere with a radius of 10 mm.     

Nanoparticles size modifications during femtosecond laser ablation of nickel in vacuum

Nanoparticles were synthesized by irradiating a nickel target with femtosecond laser pulses in high vacuum, and subsequently analyzed. The proof-of-principle experiments aim to modify the size characteristics of the produced nanoparticles. For nickel it is found that: (i) ultraviolet laser pulses lead to a remarkable change in the nanoparticles size distribution with respect to visible laser pulses; (ii) irradiation of the femtosecond pulses induced ablation plume with a second, delayed ultraviolet laser pulse can change the size characteristics of the produced nanoparticles.     

飞秒强激光经氩气和氩团簇的传播

通过数值求解三维电场传播方程,理论模拟了飞秒强激光脉冲（50 fs,1016 w/cm2）在氩气和中等尺寸氩团簇中的传播效应.结果表明,飞秒强激光脉冲经氩气传播将发生频谱蓝移展宽和光束发散;而经中等尺寸氩团簇传播,则存在一定程度的自聚焦效应.     

Talbot effect under illumination of double femtosecond laser pulses

The Talbot effect under illumination of double femtosecond laser pulses has been reported. Spectrums of double femtosecond laser pulses with phase differences are quite different from that of one single femtosecond laser pulse. Therefore, the Talbot images of the double femtosecond laser pulses with phase differences are different from that of one single femtosecond laser pulse. Specifically, for the phase difference corresponding to π, the Talbot image shows the largest difference from that of one single pulse. Experimental results are in good agreement with the theoretical analysis. The behaviors of Talbot images under double femtosecond laser pulses illumination cannot be obtained under one femtosecond laser pulse, monochromatic or polychromatic light illumination. Therefore, it is a new interesting optical phenomenon for the Talbot effect which should have potential applications.     

Microstructure fibers as frequency-tunable sources of ultrashort chirped pulses for coherent nonlinear spectroscopy

Microstructure fibers are shown to allow the creation of new tunable sources for femtosecond nonlinear spectroscopy. These fibers provide a high efficiency of frequency upconversion of regeneratively amplified femtosecond pulses of a Cr:forsterite laser, permitting the generation of subpicosecond anti-Stokes pulses with a smooth temporal envelope and a linear positive chirp. These pulses from a microstructure fiber were used to measure the spectra of coherent anti-Stokes Raman scattering (CARS) of toluene solution by cross-correlating these pulses with the femtosecond second-harmonic output of the Cr:forsterite laser in boxcars geometry (XFROG CARS). PACS 42.65.Wi; 42.81.Qb