共查询到20条相似文献,搜索用时 31 毫秒
1.
G.X. Chen M.H. Hong Q. He W.Z. Chen H.I. Elim W. Ji T.C. Chong 《Applied Physics A: Materials Science & Processing》2004,79(4-6):1079-1082
Carbon nanoparticles were prepared by pulsed laser ablation in argon gas for studying their formation, properties and applications. The nanoparticles were produced at different background pressures and different substrate temperatures, respectively. Micro-Raman spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to analyze the samples. Nonlinear optical limiting properties of the carbon nanoparticles were characterized using nanosecond laser pulses. Uniform carbon nanoparticles can be synthesized in a background gas for nonlinear optical applications. PACS 61.46.+w; 81.07.-b; 78.20.-e 相似文献
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碳纳米粒子悬浮液具有良好的光限幅性质,是一种优良的宽波段光限幅材料。通过热传导方程和米氏散射理论建立了微气泡半径与入射光能量、碳纳米粒子悬浮液散射系数和透过率的理论模型。采用Matlab数值模拟了散射系数随微气泡尺寸因子的变化关系,碳纳米粒子悬浮液光限幅性能随入射光能量的变化规律。研究了气泡尺寸因子、入射激光能量以及波长对碳纳米粒子悬浮液光限幅特性的影响。研究发现当激光能量达到一定值时,微气泡的半径保持恒定,不再随入射激光能量的增加而增加。微气泡尺寸的增大对碳纳米粒子悬浮液的透过率有着显著的影响。同时,碳纳米粒子悬浮液对不同入射光波长和光能表现出不同的光限幅性能。研究结果为实验研究提供了理论指导。 相似文献
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We have investigated the nonlinear response of the silver nanoparticle samples in a low-power regime of electromagnetic field based on nonlocal thermo-optic models. In this work, the experimental investigation of the thermo-optic nonlinear response of Ag colloids containing different size of silver nanoparticles is reported. The colloidal nanoparticle samples were synthesized by nanosecond pulsed laser ablation of Ag bulk in acetone. The sample containing Ag was characterized by linear absorption spectroscopy and transmission electron microscopy. Using the z-scan technique, the behavior of thermal nonlinear refractive index of colloid was studied at different concentrations of silver nanoparticles. Observation of asymmetrical configurations of the z-scan data indicates that nonlinear refraction occurring in the Ag samples is related to the thermo-optical process. The optical limiting here is due to nonlinear refraction of the samples arising from thermal lens formation under low-power CW excitation. When the laser power is low, the self-defocusing effect is mainly dominated by surface plasmon resonance effect. Results show that with increasing concentration of nanoparticles in acetone, the nonlinear refractive index increases while the threshold power of optical limiting decreases. 相似文献
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Nanoparticles of lead sulfide (PbS) have been prepared by a surfactant micelle template-inducing reaction. These nanoparticles were dispersed in ethanol and investigated for their nonlinear optical properties by nanosecond laser pulses. Broadband optical limiting effects have been observed at the wavelengths of 355, 1064, and 430 nm and every 30 nm from 470 to 620 nm. The nonlinear light-scattering process in the suspensions of PbS nanoparticles was characterized at the wavelength of 532 nm. Nonlinear absorption and nonlinear scattering were deduced to be the mechanisms for the broadband optical limiting performance. The origins of the nonlinear scattering were discussed. 相似文献
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R. A. Ganeev A. I. Ryasnyanskii A. L. Stepanov M. K. Kondirov T. Usmanov 《Optics and Spectroscopy》2003,95(6):967-975
Nonlinear optical characteristics of copper and silver nanoparticles in glass host matrices are studied by the Z-scan method at the wavelength of a Nd:YAG laser (λ=1064 nm) in a field of picosecond pulses. It is found that the third-order nonlinear susceptibility is more pronounced in glasses with copper nanoparticles than in glasses with silver nanoparticles. On the basis of experimental data obtained for samples with copper nanoparticles synthesized by ion implantation, it is shown for the first time that the nonlinear absorption of laser radiation with a wavelength lying out of the plasmon resonance region can be caused by a two-photon effect in metal particles. The character of the optical limiting process in the samples with copper nanoparticles when two-photon absorption is involved is discussed. 相似文献
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The effect of thickness on the nonlinear optical properties of Au nanoparticles which produced by laser ablation of high purity gold bulk in distilled water were investigated by employing different optical techniques. Experiments were performed on the 0.3, 0.6, and 1 mm thickness cells of Au nanoparticles-fluid. The effect of nonlinear refractive index of samples on the laser beam broadening was observed. The optical limiting behavior of samples is investigated by measuring the transmitted intensity of the laser beam through the samples. The third order nonlinearity of Au nanoparticles-fluid was measured by using Z-scan data. Results show a positive second order refractive index and absorption coefficient for Au nanoparticles-fluid that are increased in due of increasing the thickness of the cells. The magnitudes of both real and imaginary parts of third order susceptibility of samples are increased by increasing the thickness. 相似文献
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German Salazar-Alvarez Eva Björkman Cesar Lopes Anders Eriksson Sören Svensson Mamoun Muhammed 《Journal of nanoparticle research》2007,9(4):647-652
Microemulsions composed of normal or inverse micellar solutions and aqueous suspensions of pristine (uncoated) or silica-coated
iron oxide nanoparticles, mainly γ-Fe2O3, were synthesised and their optical limiting properties investigated. The microemulsions are colorless solutions with high
transparency for visible wavelengths while the aqueous suspensions of iron oxide are of pale yellow colour. Optical limiting
experiments performed in 2 mm cells using a f/5 optical system with a frequency doubled Nd:YAG laser delivering 5 ns pulses
with 10 Hz repetition rate, showed clamping levels of ∼3 μJ for the suspensions of both pristine and silica-coated iron oxide
nanoparticles. A strong photoinduced nonlinear light scattering was observed for the water-in-oil microemulsion and the aqueous
suspensions of nanoparticles while oil-in-water microemulsions did not show a significant nonlinear effect. Measurements carried
out using an integrating sphere further verified that the photoinduced nonlinear light scattering is the dominating nonlinear
mechanism while the nonlinear absorption of iron oxide nanoparticles is negligible at 532 nm. 相似文献
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Structural modification of carbon nanotubes in combination with metallic nanoparticles is reported. An enhancement in the nonlinear optical refraction of multi-wall carbon nanotubes by the incorporation of platinum nanoparticles was observed. Comparative results were analyzed taking into account the participation of single-wall carbon nanotubes that originate a decrease in the nonlinear optical response of the multi-wall carbon nanotubes integrating a thin film. A Nd:YAG laser system featuring 532 nm wavelength with 4 ns pulse duration in a two-wave mixing experiment was employed for exploring the studied optical nonlinearities of the samples. The contribution of optical processes to mechanical characteristics dependent on high optical irradiance in carbon nanotubes was described. A variation in the mass density associated to the optically irradiated tubes allowed us to calculate the change in Young's modulus in a thin film configuration. The estimation of an opto-mechanical phenomenon was based on the evaluation of the nonlinearity of index responsible for the optical Kerr effect. According to Raman and optical evaluations, the inclusion of metallic nanoparticles in carbon structures results in a modification of surface that also gives origin to noticeable optical Kerr nonlinearities. Potential applications for developing laser-induced controlled opto-mechanical nanohybrid systems can be contemplated. 相似文献
10.
使用532nm,8ns激光脉冲研究了两种新型的基于富勒烯C60结构体系的金纳米粒子合成物的光学非线性.Z-scan实验结果和理论分析的比较表明,材料的非线性吸收强烈地依赖于材料中的配合体,而非线性折射主要来自金纳米粒子的贡献.而且与熟知的C60甲苯溶液光限幅特性作了比较,分析了光限幅机理.
关键词:
60结构体系')" href="#">基于富勒烯C60结构体系
金纳米粒子
等离子体
光限幅 相似文献
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钴卟啉溶液的光限幅特性研究 总被引:1,自引:1,他引:0
对大分子有机化合物钴卟啉的非线性光学特性在 4 5 7 9,4 88和 5 14 5nm三个连续激光波长下进行了研究。用单光束z scan技术测到三个曲线均是先出现峰值后出现谷值 ,按照Sheik bahae等人的理论该样品的非线性折射率为负值 ,即样品具有热自散焦效应。反饱和吸收特性的研究结果得到三个透射率T随入射激光功率的增大而减小的曲线 ,表明该样品在这三个波长下均呈现出反饱和吸收效应。众所周知 ,热自散焦效应和反饱和吸收效应都能导致光限幅。文章的实验结果也表明 :钴卟啉在三个波长下均具有光限幅特性 ,限幅阈值随着波长的减小而减小 ;其光学限幅效果好且限幅阈值低 ,是一种有较大潜在应用价值的新型光限幅材料。因此 ,可以利用这两种效应对钴卟啉的共同作用 ,制成新型光限幅器件 相似文献
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The investigation of nonlinear optical characteristics of ethanol solution doped with is presented. A large thermal-induced third-order nonlinear refractive index up to silver nanoparticles 1.941× 10^-7 cm2/W is obtained from the mixed solution under 488-nm continue wave (CW) laser irradiation, which may result from surface plasmon resonance (SPR) enhancement effect of silver nanoparticles as well as high thermo-optic coefficient and low thermal conductivity of ethanol. Obvious spatial self-phase modulation and influence of thermal-induced negative lens effect are observed when a beam propagates through this solution, indicating promising applications such as optical limiting, beam flattening, and so on. 相似文献
13.
A large number of individual single-walled carbon nanotubes (SWNTs) were obtained by dilution of nanotube dispersions in N-methyl-2-pyrrolidone (NMP). Up to 70% individual SWNTs are contained in the NMP dispersions with concentrations of less than 4.0×10-3 mg/mL. The nonlinear optical and optical limiting properties of SWNT dispersions were studied by using the Z-scan technique at 532 nm. As the concentration of SWNTs is increased, the nonlinear extinction (NLE) and optical limiting effects improve significantly, while the limiting thresholds decrease gradually. The individual SWNTs show similar NLE effect to zinc phthalocyanine nanoparticles, while also exhibiting larger NLE coefficients than Mo6S4.5I4.5 nanowires. 相似文献
14.
Nanostructured silver and linear carbon chain (LCC) particle water colloids were prepared by a pulsed laser ablation procedure. Sample's optical transmission response was investigated in the 190–900 nm range, the third-order nonlinear optical properties were studied using the z-scan method and a nanosecond laser. The silver nanoparticles induce a structural change in the LCC colloids: the mixed Ag and LCC optical absorption looses the signature of the short carbon chain maintaining the features attributable to the longer ones. The stability of LCC colloids and their nonlinear response are remarkably improved by the Ag nanoparticles addition to the carbon water colloids. The Ag nanoparticles induce a limiting threshold reduction, an increased nonlinear absorption coefficient β and a marked asymmetrical peak/valley profile of the (Ag:LCC)mix when compared to the LCC. All these nonlinear contributions determine the increase of the third order susceptibility, while maintaining a significantly high linear transmission value (75%) at 532 nm and high photostability. The magnitude of the nonlinear optical response of these nanohybrids makes them promising candidates for potential optoelectronic applications. 相似文献
15.
R. A. Ganeev A. I. Ryasnyanskii A. L. Stepanov T. Usmanov 《Physics of the Solid State》2003,45(7):1355-1359
The nonlinear absorption in copper nanoparticles contained in glass matrices is investigated using the Z-scan technique at the wavelength of a picosecond Nd: YAG laser (λ=1064 nm). The experimental data obtained for copper nanoparticle-containing composites synthesized through ion implantation are analyzed. It is demonstrated for the first time that, upon exposure to laser radiation at frequencies outside the range of surface plasma resonance, the nonlinear absorption in metallic particles can be caused by the two-photon effect. The optical limiting due to two-photon absorption is discussed for composites containing copper particles. 相似文献
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A. V. Sokolov A. L. Nikolaeva A. Yu. Vlasov I. M. Kislyakov A. V. Volkova S. A. Povarov 《Optics and Spectroscopy》2017,123(2):305-308
The possibilities of correcting the functional properties of nonlinear optical limiters based on carbon nanoparticles using polymer dopants have been considered. The results of analyzing the characteristics of nonlinear optical limiting of a suspension of carbon black with addition of sodium dodecylbenzene sulfonate and polyvinyl alcohol are given. The forms in which particles exist in the suspension have been investigated by different physicochemical methods. Optical measurements have confirmed the efficiency of these additives. 相似文献
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可溶性高聚物-多壁碳纳米管复合物的吸收光谱和光限幅性能研究 总被引:1,自引:1,他引:0
合成了三种可溶性高聚物嫁接的多壁碳纳米管复合物,包括聚乙烯基咔唑-多壁碳纳米管复合物(MWNTs-PVK),聚苯乙烯-多壁碳纳米管复合物(MWNTs-PSt)和聚甲基丙烯酸甲酯-多壁碳纳米管复合物(MWNTs-PMMA)。合成样品的TEM图显示出高聚物成功地包裹在碳纳米管外。样品的氯仿溶液UV-Vis 吸收谱显示,复合物的紫外区与纯的多壁碳纳米管不同,有一些复杂的特征吸收峰,反映了高聚物与碳纳米管共价连接的作用。利用Z扫描技术通过527 nm的纳秒激光脉冲激发研究了这三种复合物的非线性光学性质和光限幅性能。这三种复合物的氯仿溶液的光限幅性能很相似,并且优于纯多壁碳纳米管氯仿悬浮液和C60甲苯溶液。为解释观察到的结果,研究了样品的非线性折射,非线性吸收和非线性散射机制。结果显示,非线性吸收是引起样品光限幅的主要机制。 相似文献