共查询到19条相似文献,搜索用时 125 毫秒
1.
《中国光学与应用光学文摘》2006,(3)
TN241 2006032049物理参数对光限幅效应的影响=Influence of optical phys-ics parameters on optical li miting effect[刊,中]/刘晓杰(哈尔滨师范大学呼兰学院物理系.黑龙江,呼兰(150500)) ,尹海涛∥应用光学.—2006 ,27(1) .—9-11根据非线性吸收模型,推导出光限幅阈值表达式,并以表达式为理论依据,利用配位聚合物[Cd(L4)(SO4)( H2O)2]n在波长532 nm、脉冲宽度为40 ps的条件下所获得的实验数据,分析研究非线性吸收参数、线性透过率和有效激发态吸收截面等物理参数对光限幅效应的影响。以此为基础,研究了激光防护材料的非线性光学特性… 相似文献
2.
3.
4.
5.
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
6.
7.
8.
通过光限幅、Z扫描、非线性吸收和散射能量分布实验,研究了碳纳米管悬浮液对532 nm激光的限幅机理以及样品厚度对光限幅机理的影响。结果表明:碳纳米管悬浮液的光限幅机理并非单纯的非线性散射,对低能量入射激光光限幅特性主要源于对入射激光的非线性吸收;对高能量入射激光,碳纳米管的吸收效应和它电离形成的微等离子体以及液体汽化所形成气泡散射效应的共同作用,使其具有较强的光限幅能力,对浓度一定的悬浮液,增加样品厚度虽然会增强其限幅效果,但却会减弱其非线性散射效应。 相似文献
9.
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
11.
We report the investigations of thermally induced third-order nonlinear optical and optical limiting characterizations for various concentrations of acid blue 40 dye in N,N-Dimethyl Formamide, studied by employing z-scan technique under cw He–Ne laser irradiation at 633 nm wavelength. The samples exhibited nonlinear absorption and nonlinear refraction under the experimental conditions. For lower concentration, the samples display both saturable absorption (SA) and reverse saturable absorption (RSA); whereas with increase in concentration, RSA behaviour prevails. The estimated values of the effective coefficients of nonlinear absorption βeff, nonlinear refraction n2 and third-order nonlinear susceptibility χ(3) were found to be of the order of 10?2 cm/W, 10?4 esu and 10?6 esu respectively. Multiple diffraction rings were observed when the samples were exposed to laser beam due to refractive index change and thermal lensing. The effect of concentration and the laser intensity on the self-diffraction ring patterns was studied experimentally. The acid blue 40 dye also exhibited strong optical limiting properties under cw excitation and reverse saturable absorption is found to be the dominant nonlinear optical process leading to the observed nonlinear behaviour. 相似文献
12.
Mathew George C.I. Muneera C.P. Singh K.S. Bindra S.M. Oak 《Optics & Laser Technology》2008,40(2):373-378
The nonlinear optical absorption, refraction and optical limiting behaviour of an organic dye, neutral red, were investigated under excitation with nanosecond laser pulses at 532 nm. The nonlinear optical responses of the material were studied both in solution and solid film, made in methanol and polyvinyl alcohol, respectively, using single-beam Z-scan technique. The open aperture Z-scans of the solution samples displayed a switch over from saturable absorption to enhanced absorption with increase in input intensity. Theoretical fit to the experimental data indicated that the dominant mechanism of nonlinear absorption is two-photon absorption. The closed aperture Z-scans of both the samples denoted positive nonlinearity, which was three orders larger in magnitude in solid film, compared with that in solution. The results of optical limiting experiments revealed that neutral red exhibited strong optical limiting of nanosecond laser pulses with a threshold lower than that of C60 in toluene. 相似文献
13.
利用纳秒级脉冲量激光的Z 扫描方法对不同层数石墨烯薄膜在3 m~5 m中红外波段的光限幅效应开展了研究,获得的开孔Z扫描曲线均呈现出单一谷结构,而闭孔Z扫描曲线没有明显的峰谷对称结构。通过对开孔Z扫描实验数据进行数值模拟,分别得到3层石墨烯在3.010 m、3.522 m、4.326 m和4.880 4 m 4个中心波长处的三阶非线性吸收系数和光限幅阈值分别为11.3910-7cm/W、10.6110-7cm/W、9.7510-7cm/W、8.8110-7cm/W和3.49 J/cm2、3.75 J/cm2、4.11 J/cm2、4.55 J/cm2;3层、5层和7层石墨烯在3.522 m中心波长处的三阶非线性吸收系数和光限幅阈值分别为10.6110-7 cm/W、11.3210-7 cm/W、11.9510-7 cm/W和3.75 J/cm2、3.41 J/cm2、3.32 J/cm2。实验数据表明,石墨烯在中红外波段产生了较强的非线性反饱和吸收而具有明显的光限幅效应。 相似文献
14.
Quanshui Li Chunling Liu Qihuang Gong Jining Gao Limin Qi 《Journal of nanoparticle research》2009,11(4):989-993
In order to reveal the optical limiting mechanisms of semiconductor hollow spheres, the nonlinear optical properties of CuS
and Cu2O hollow spheres were investigated via the fluence-dependent transmittance and the nonlinear scattering measurements. The
CuS and Cu2O hollow spheres have similar morphologies and different types of optical band-gap. The experimental results show that the
optical limiting performance of CuS is better than that of Cu2O, although the nonlinear scattering of Cu2O is stronger than that of CuS. Free-carrier absorption based on the delocalized carriers (holes) in CuS is believed to play
an important role in the optical limiting effects. The merits of the structure of semiconductor hollow spheres used for optical
limiting were discussed. 相似文献
15.
Nonlinear optical absorption of fluorine-functionalized graphene oxide (F-GO) solution was researched by the open-aperture Z-scan method using 1064 and 532 nm lasers as the excitation sources. The F-GO dispersion exhibited strong optical limiting property and the fitted results demonstrated that the optical limiting behavior was the result of a two-photon absorption process. For F-GO nanosheets, the two-photon absorption coefficients at 1064 nm excitation are 20% larger than the values at 532 nm excitation and four times larger than that of pure GO nanosheets. It indicates that the doping of fluorine can effectively improve the nonlinear optical property of GO especially in infrared waveband, and fluorine-functionalized graphene oxide is an excellent nonlinear absorption material in infrared waveband. 相似文献
16.
溶剂对光致变色材料-乙基红的光学特性影响 总被引:2,自引:0,他引:2
研究了溶剂性质对光致变色材料乙基红光学性质的影响.用吸收谱测定了乙基红染料在不同溶剂中的溶剂化位移.对相同浓度多种乙基红溶液进行了Z-scan测量,测量了不同乙基红溶液的光限幅效应,并讨论了其与溶剂之间的关系.随极性增加,吸收谱蓝移,可以通过选择不同溶剂,改变非线性材料的应用窗口.实验结果表明,在连续光照射下,乙基红溶液的非线性折射主要由热效应引起,非线性折射系数n2受溶剂的热学性质影响较大.此外,Z-scan结果中的非线性吸收为饱和吸收.至于光限幅效应,主要受热效应影响,但亦可由吸收谱预测出在某波长处的动态范围.得出的结论有助于偶氮染料作为非线性材料的应用. 相似文献
17.
Oxidized dichloromethane solutions of cis-Mo(CO)4(PPh3)2 stabilized by the addition of excess PPh3 exhibit unusual large molecular second-order hyperpolarizabilities with minimal linear absorption. To better understand the mechanism by which this occurs, DFWM, Z-scan and optical limiting experiments have been carried out on oxidized dichloromethane solutions of cis-Mo(CO)4(PPh3)2 using 5.8 ns laser pulses at 532 nm. Our results demonstrate that the mechanism by which the oxidized species enhance the third-order nonlinear response is not dominated by thermal effects, but is instead due to the strong nonlinear absorption and nonlinear refraction of the oxidized species. Moreover, the oxidized species shows very strong optical limiting properties. Such complexes would be very interesting third-order nonlinear optical materials for optical limiting applications. 相似文献
18.
The third-order optical nonlinearities of [(CH3)4N]Au(dmit)2 (dmit = 4,5-dithiolate-1,3-dithiole-2-thione) at 532 nm and 1064 nm are investigated using the Z-scan technique with pulses of picoseconds duration. The Z-scan spectra reveal a strong nonlinear absorption (reverse saturable absorption) and a negative nonlinear refraction at 532 nm. No nonlinear absorption is observed at 1064 nm. The molecular second-order hyperpolarizability γ for the [(CH3)4N]Au(dmit)2 molecule at 532nm is estimated to be as high as (2.1 ±0.1) × 10^-31 esu, which is nearly three times larger than that at 1064 nm. The mechanism responsible for the difference between the results is analysed. Nonlinear transmission measurements suggest that this material has potential applications in optical limiting. 相似文献
19.
We report experimental results on a highly efficient optical limiter that uses a three-mirror, multipass ring configuration. The optical limiter's enhanced performance is based on the accumulative effect that is achieved when the laser beam passes through the sample several consecutive times. Its feasibility was demonstrated for media with different limiting action processes, namely, reverse saturable absorption, nonlinear scattering, and thermal lensing. We employed a frequency-doubled, Q-switched, 10-ns Nd:YAG laser operating at a 5-Hz repetition rate. 相似文献