共查询到20条相似文献,搜索用时 110 毫秒
1.
2.
Lingling Ran Zhongyi Guo Shiliang Qu 《Applied Physics A: Materials Science & Processing》2010,100(2):517-521
Self-organized periodic surface structures on ZnO have been observed after multiple linearly polarized femtosecond laser pulse
irradiation. The observed self-organized structures are attributed to the second harmonics in the sample surface excited by
the incident laser. The grating orientation could be adjusted by the laser polarization direction. We also find that fluences
play an important role in the formation of self-organized nanostructures. 相似文献
3.
Arrays of conical-like spikes can be formed on silicon surface after irradiated with femtosecond laser pulses in ambient of SF6 or N2. In this article, we report our observations on how the shape of the spikes formed on silicon surface varies with the polarization of laser beam. The experimental results show that, with circular polarized laser irradiation, the shape of the spikes is conical; however, with linearly polarized laser irradiation, the spikes show elliptic conical shape, and the long-axes are perpendicular to the direction of the polarization of laser beam. The asymmetric shape of spikes produced by linearly polarized laser beam can be explained by considering the polarization dependence of Fresnel-refraction. 相似文献
4.
5.
X.J. Wu T.Q. Jia F.L. Zhao M. Huang N.S. Xu H. Kuroda Z.Z. Xu 《Applied Physics A: Materials Science & Processing》2007,86(4):491-495
Uniform arrays of periodic nanoparticles with 80-nm period are formed on 6H-SiC crystal irradiated by circularly polarized
400-nm femtosecond laser pulses. In order to understand the formation mechanism, the morphology evolvement as a function of
laser pulse energy and number is studied. Periodic nanoripples are also formed on the sample surface irradiated by linearly
polarized 400-, 510- and 800-nm femtosecond laser pulses. All these results support well the mechanism that second-harmonic
generation plays an important role in the formation of periodic nanostructures.
PACS 79.20.Ds; 42.62.Cf; 61.80.Ba; 81.05.Cy; 78.30.Am 相似文献
6.
In this Letter, we generate laser-induced periodic surface structures (LIPSSs) on platinum following femtosecond laser pulse irradiation. For the first time to our knowledge, we study the morphological profile of LIPSSs over a broad incident angular range, and find that the morphological profile of LIPSSs depends significantly on the incident angle of the laser beam. We show that LIPSS grooves become more asymmetric at a larger incident angle, and the morphological profile of LIPSSs formed at an incident angle over 55° eventually resembles that of a blazed grating. Our study suggests that the formation of the blazed groove structures is attributed to the selective ablation of grooves through the asymmetric periodic surface heating following femtosecond pulse irradiation. The blazed grooves are useful for controlling the diffraction efficiency of LIPSSs. 相似文献
7.
Yang Yang Jianjun Yang Chunyong Liang Hongshui Wang Xiaonong Zhu Dengfeng Kuang Yong Yang 《Applied Physics A: Materials Science & Processing》2008,92(3):635-642
Generation of self-organized sub-wavelength surface structures on a nickel–titanium alloy plate by femtosecond laser pulses
is investigated experimentally through line-scribing experiments in air. It is found that Bragg-like relief gratings, with
the orientation perpendicular to the laser polarization, are formed over the entire laser-scribed regions. The average period
is measured as 630±30 nm. Distinctive features of these novel surface structures include nanoparticle-covered grating ridges
and the maintainable spatial period regardless of incidence angles. With different laser parameters and sample scan speeds,
sub-wavelength grating structures can evolve into cellular-like nanotextures. Optimal conditions for forming these surface
structures are determined in terms of laser energy and scan speed. Elementary analyses of the structured surfaces by X-ray
diffraction and photoelectron spectroscopy reveal that both the crystal structures and the chemical elements can remain in
their original states, but the surface grains are refined and the atomic percentages are varied after femtosecond laser treatments. 相似文献
8.
采用了不同能量的单脉冲和多脉冲飞秒激光对LiNbO3晶体进行烧蚀,并刻蚀了表面衍射型光栅.通过扫描电镜和原子力显微镜观察了烧蚀点的形貌特征,首次发现利用单束飞秒激光脉冲对LiNbO3晶体烧蚀,可以得到超衍射极限的烧蚀点,当聚焦光斑直径约为2μm、能量为170nJ的单脉冲飞秒激光作用时,烧蚀点的直径约为400nm,100nJ,17个脉冲作用时烧蚀点的直径约为800nm.同时可以观察到在能量较低的多脉冲飞秒激光作用下, LiNbO3晶体呈现出大约200nm周期性分布的波纹状结构.实验结果表明,选择合适参数的飞秒激光脉冲可以对LiNbO3晶体进行超衍射极限加工,这对于利用飞秒激光制作LiNbO3基质的微纳光电子器件有十分重要的意义. 相似文献
9.
Modulation grating has been achieved by two interfered femtosecond laser pulses on the surface of the silica glass. The modulation grating formed at the middle of each bulge of the common grating and was attributed to the higher-order modulation arising from second-harmonic generation (SHG) of the femtosecond laser pulse incident to the surface of silica glass. The periods and depths of the fundamental grating and the modulation grating have been observed by using an atomic force microscopy (AFM). Experimental results show that the average depth of the modulation grating is nearly a half of the depth of the fundamental grating. 相似文献
10.
H.L. Ma Y. Guo M.J. Zhong R.X. Li 《Applied Physics A: Materials Science & Processing》2007,89(3):707-709
Periodic nanostructures are observed on the surface of ZnSe after irradiation by a focused beam of a femtosecond Ti:sapphire
laser, which are aligned perpendicular to the laser polarization direction. The period of self-organized grating structures
is about 160 nm. The phenomenon is interpreted in terms of interference between the incident light field and the surface scattered
wave of 800-nm laser pulses. With the laser polarization parallel to the moving direction we produce long-range Bragg-like
gratings by slowly moving the crystal under a fixed laser focus. The nanograting orientation is adjusted by laser polarization
and the accumulation effect.
PACS 81.16.Rf; 78.67.-n; 33.80.Rv; 82.53.Mj; 81.16.-c 相似文献
11.
A photonic crystal fibre Brillouin laser based on fibre Bragg grating Fabr-Perot cavity is presented. A highly nonlinear photonic crystal fibre 25 m in length is used as Brillouin gain medium and fibre Bragg grating Fabry-Perot cavity is chosen in order to enhance the laser conversion efficiency and suppress the higher-order Stokes waves. The laser reaches the threshold at input power of 35 mW, and the experimental laser conversion efficiency achieves 18% of the input power of 140 mW and does not show higher-order Stokes waves. A photonic crystal fibre Brillouin laser with shorter fibre length and lower threshold is experimentally realized. 相似文献
12.
飞秒激光在6H SiC晶体表面制备纳米微结构 总被引:2,自引:0,他引:2
激光诱导周期性纳米微结构在多种材料包括电介质、半导体、金属和聚合物中观察到。研究了800nm和400nm飞秒激光垂直聚焦于6H SiC晶体表面制备纳米微结构。实验观察到800nm和400nm线偏光照射样品表面分别得到周期为150nm和80nm的干涉条纹,800nm圆偏振激光单独照射样品表面得到粒径约100nm的纳米颗粒。偏振相互垂直的800nm和400nm激光同时照射晶体得到粒径约100nm的纳米颗粒阵列,该纳米阵列的方向随400nm激光强度增加而向400nm偏振方向偏转。利用二次谐波的观点对以上纳米结构的形成给出了解释。 相似文献
13.
14.
Xiao Hu Juan Song Qinling Zhou Luyun Yang Xiaodan Wang Congshan Zhu Jianrong Qiu 《中国光学快报(英文版)》2008,6(5)
The femtosecond laser induced void array inside Al2O3 crystals was discussed.The void array was formed spontaneously under the irradiation of a single beam of infrared femtosecond laser which was focused at a fixed point inside the Al2O3 crystal sample.It was found that the regular voids only could be fabricated near the sample surface,which was different from the situation in CaF2 single crystal reported before.The possible mechanism of the phenomena was also discussed. 相似文献
15.
Takuro Tomita Ryota Kumai Hidenori Nomura Shigeki Matsuo Shuichi Hashimoto Ken Morita Toshiro Isu 《Applied Physics A: Materials Science & Processing》2011,105(1):89-94
Spontaneous nanostructure formations on roughened and smooth silicon surface by the femtosecond laser irradiation with the
repetition rate of 100 kHz were systematically studied. In addition to the widely accepted so-called coarse ripple, which
has the period analogous to the wavelength of the laser beam and aligns perpendicularly to the electric field of the incident
laser beam, the ripple which has the period similar to the wavelength of the incident laser beam but aligns parallel to the
electric field of the laser beam was observed on the roughened surface for the lower fluence and the higher number of pulse
irradiation. Furthermore, the ensemble of dots formed by the enhancement of the local electric field was found on the roughened
surface. This structure is preferentially formed around the scratches aligned perpendicularly to the electric field of the
laser beam. These novel nanostructures are considered to be peculiar to the femtosecond laser irradiation and open the possibilities
for precise control of the spontaneous nanostructure formation by femtosecond laser irradiation. 相似文献
16.
Coherent linking of periodic nano-ripples on a ZnO crystal surface induced by femtosecond laser pulses 总被引:1,自引:0,他引:1
X. D. Guo R. X. Li Y. Hang Z. Z. Xu B. K. Yu Y. Dai B. Lu X. W. Sun 《Applied Physics A: Materials Science & Processing》2009,94(2):423-426
We demonstrate the coherent linking of periodic nano-ripples formed on the surface of ZnO crystals induced by femtosecond
laser pulses. By adjusting the distance between two laser scanning zones, the periodic nano-ripples induced by two separated
laser writing processes can be coherently linked and the ZnO nanograting with much longer grooves is therefore produced. The
length limitation of this kind of nanograting previously set by the laser focus size is thus overcome. The micro-Raman mapping
technique is used to evaluate the quality of coherent linking, and the underlying physics is discussed. The demonstrated scheme
is promising for producing large-size self-organized nanogratings induced by femtosecond laser pulses. 相似文献
17.
基于由光子晶体光纤飞秒激光器产生的高重复频率飞秒激光搭建了飞秒激光微加工系统,利用LabVIEW编写程序精密控制三维移动平台的移动路径和高速快门,在加工功率为1.5W、移动速率为1mm/s时,利用直写技术在无胶铬版上得到了微米量级的任意形状的平面衍射光栅。利用CCD相机对光栅制备过程进行实时监视,保证了光栅的加工质量。制备的光栅在显微镜下观察,条纹边缘清晰、线纹粗细均匀。使用He-Ne激光照射加工的光栅,可以获得清晰、稳定、与理论符合很好的夫琅和费(Frauhofer)衍射图样,显示了所加工的光栅具有良好的光学性能。实验结果也表明了光子晶体光纤飞秒激光在光栅制作过程中所具备的良好的加工性能。 相似文献
18.
不同烧蚀条件下飞秒激光脉冲诱导ZnO纳米结构研究 总被引:6,自引:5,他引:1
烧蚀条件对飞秒激光脉冲诱导氧化锌纳米结构有重要影响.研究了800 nm,150 fs,250 kHz的飞秒激光脉冲分别在空气中,去离子水中以及无水乙醇中垂直聚焦于氧化锌晶体表面,诱导形成不同形态的纳米结构.实验结果表明,在空气中利用飞秒激光脉冲辐照样品表面,形成了周期为180 nm的纳米线;在去离子水中辐照诱导形成了由氧化锌纳米线聚集而成的"纳米球";在无水乙醇中形成出现分叉结构的纳米线.拉曼光谱分析辐照前后晶体晶相结果表明,形成的纳米结构相对于辐照前特征峰437 cm-1强度有所下降,在570 cm-1处的峰值则显著增强.分析了在各种烧蚀条件下诱导形成纳米结构的演化过程以及物理机理. 相似文献
19.
《中国光学快报(英文版)》2016,(12)
The self-formation of periodic subwavelength ripples by linear polarized femtosecond laser scanning planar and non-planar tungsten targets on the employed laser wavelength, scanning speed, and energy fluence are examined systematically. The results show that, for a certain laser wavelength, the scanning conditions have no obvious effect to the morphological features of grating structures in the threshold range of laser fluence. The spatial structured period of gratings can be self-consistently interpreted by recently presented physical model of surface two-plasmon resonance. The subwavelength structures on cylindrical surface would be a good method to realize unique surface functions on complex surface of micro-devices. 相似文献
20.
突破传统涡旋光场束缚,发展短波极紫外涡旋光场是实现阿秒脉冲偏振控制的有效途径.本研究利用自制的平场光栅光谱仪和超快时间保持的单色仪,以800 nm,35 fs高斯或具有偏振奇点的涡旋光脉冲驱动诱导氩原子产生高次谐波,分别获得相应的高次谐波光谱以及谐波谱单阶光源的分布.实验结果表明,基于高次谐波产生实现近红外波段的涡旋光束特性转移到极紫外波段,优化后的极紫外涡旋可以实现每秒108光子数输出.同时发现极紫外波段的涡旋场和高斯场高次谐波产生具有相似相位匹配机制.基于高次谐波产生的极紫外波段的偏振涡旋光为探究和操控原子分子量子态的含时演化动力学以及形成阿秒矢量光束提供了重要的方法和技术手段. 相似文献