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侧链共轭的聚噻吩衍生物具有拓宽的共轭程度,有望成为一类性能优良的三阶非线性光学材料.合成了一种侧链共轭的噻吩共聚物:聚 -噻吩(POTVTh-Th),该聚合物与其均聚物相比,吸收光谱发生了明显的红移,禁带宽度为1.72eV.采用Z扫描技术在800nm下用飞秒激光器研究了该聚合物溶液和薄膜的三阶非线性光学特性,结果表明该共聚物四氢呋喃溶液中的三阶非线性极化率为8.84×10-10esu,聚合物薄膜的三阶非线性极化率为7.25×10-9esu,分别是其
关键词:
侧链共轭
噻吩共聚物
三阶非线性极化率
非线性吸收 相似文献
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纳米金属一陶瓷复合薄膜是纳米金属颗粒嵌埋在介质载体中形成的一种复合材料。在此体系中纳米金属的小尺寸效应、表面界面效应、量子尺寸效应、量子隧穿效应及陶瓷基体的高介电常数及介电强度,赋予此体系独特的光学特性。如高的三阶非线性光学极化率、超快的三阶非线性响应时间及高三阶非线性系数等,在电子器件和光学材料方面有着潜在的应用前景,引起了国内外学者的极大兴趣。 相似文献
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有机聚合物的非线性光学 总被引:3,自引:0,他引:3
有机聚合物是一类非常重要的非线性光学材料,这是因为它在光通信和高密度光存储等高技术领域中有良好的应用前景。有机聚合物的非线性光学性质是过去20年来理论和实验的重要研究课题。文章在简要介绍非线性光学之后,着重论述了有机聚合物光学非线性的来源和这些材料中二阶、三阶非线性光学效应及非线性光吸收的特点。最后,简要介绍了作者在有机聚合物非线性光学研究中几个近期结果,如“全光极化、三阶光学非线性的激发态增强、 相似文献
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采用射频磁控反应溅射技术与热退火处理制备了Si/SiNx超晶格材料。利用吸收光谱和X射线衍射对材料进行表征。通过皮秒脉冲激光单光束Z-扫描技术研究了该材料在非共振吸收区的三阶非线性光学特性,实验结果表明,样品的非线性折射率为负值,非线性吸收属于双光子吸收。由实验数据得到材料的三阶非线性极化率实部和虚部分别为1.27×10-7,1.51×10-8esu,该值比体硅材料的三阶非线性极化率值大5个数量级。对材料光学非线性产生的机理进行了探讨,认为材料的非线性极化率的增加来源于材料量子限制效应的增强。 相似文献
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陈自然 《原子与分子物理学报》2014,31(6)
采用密度泛函理论B3LYP/6-31+G*方法对含Y型均三嗪类衍生物的6个分子(Y1-Y6)进行几何构型优化,对其最优构型采用TD-DFT(TDB3LYP/6-31+G*)计算电子吸收光谱,用有限场FF方法及自编程序计算三阶非线性光学(NLO)性质。结果表明,6个含Y型均三嗪类有机分子的三阶非线性光学系数g值为1010数量级个原子单位(10-30 esu),显示出良好的三阶非线性光学性能。在其三支链的末端引入不同的推、拉电子基团(Y2→Y6),对其电子光谱和三阶非线性光学响应具有明显的影响。引入强供电子基团,g增大幅度较大,有利于改善体系的三阶非线性光学性质,从而可获得良好的非线性光学材料。 相似文献
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《光学学报》2021,41(8):195-205
铌酸锂晶体是一种综合性质优异的多功能光学材料。在过去几十年里,对铌酸锂晶体的研究一直是光学研究的热点之一。近年来发展起来的绝缘体上铌酸锂(LNOI),亦称为铌酸锂薄膜(LNTF),在光学领域被公认为是一项变革性技术。基于LNOI的集成光子器件让铌酸锂晶体又焕发了新生命,再次成为集成光子学的研究焦点。作为最优秀的非线性晶体之一,铌酸锂薄膜在频率转换方面是其他薄膜材料无法替代的。总结了基于铌酸锂薄膜的非线性频率转换最新研究进展,包括二阶非线性、三阶非线性、级联非线性和光学频率梳等,最后对LNOI平台上光子集成回路(PIC)的前景进行了展望。 相似文献
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采用密度泛函理论B3LYP/6-31+G*方法对含Y型均三嗪类衍生物的6个分子(Y1-Y6)进行几何构型优化,对其最优构型采用TD-DFT (TDB3 LYP/6-31+G*)计算电子吸收光谱,用有限场FF方法及自编程序计算三阶非线性光学(NLO)性质.结果表明,6个含Y型均三嗪类有机分子的三阶非线性光学系数γ值为1010数量级个原子单位(10-30 esu),显示出良好的三阶非线性光学性能.在其三支链的末端引入不同的推、拉电子基团(Y2→Y6),对其电子光谱和三阶非线性光学响应具有明显的影响.引入强供电子基团,γ增大幅度较大,有利于改善体系的三阶非线性光学性质,从而可获得良好的非线性光学材料. 相似文献
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导电高聚物的三阶非线性光学效应 总被引:4,自引:0,他引:4
最近,导电高聚物作为具有快速响应和大的X~(3) 的非线性光学材料的希望引超了足够的重视,这是因为它可能在快速光开关、非线性记忆和光晶体管等上获得应用.导电高聚物的三阶非线性光学系数X~(3),在10~(-9)─10~(-12)esu范围之内,并强烈地依赖于主链结构、高聚物链的构向和取向、共轭长度、取代基种类、掺杂程度和聚合条件等.所观察到的非线性光学效应是本征的,它可能与孤子、极化子和双极化子的光激发有关.本文讨论导电高聚物的三阶非线性光学效应的特性、来源、分子设计、研究进展和展望. 相似文献
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纳米微粒SnO2非线性光学特性的Z—扫描技术研究 总被引:5,自引:0,他引:5
利用Z-扫描技术,以调QNd:YAG激光器作光源,首镒在非共振区域研究了SnO2纳米微粒的三阶非线性光学性质,获得了三阶非线性极经系数x^(3)与双光子吸收系数β等重要依据,并对其非线性响应机制进行了探讨。 相似文献
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2-Furoic acid (2FA), an organic third order nonlinear optical single crystal, has been synthesized and grown successfully by slow solvent evaporation technique. The space group and lattice parameters of the grown crystals were obtained by single crystal X-ray diffraction analysis. The presence of the functional groups was confirmed by Fourier Transform Infrared (FTIR) spectroscopy. Optical absorption studies reveal low absorption in the UV and visible regions and the UV cut-off wavelength is found to be at 240 nm. The thermal stability of the material examined by TGA analysis, reveals that the material is thermally stable up to 130 °C. The third order nonlinear optical parameters (nonlinear refractive index, nonlinear absorption coefficient and real and imaginary parts of the third order nonlinear optical susceptibility) were derived by Z-scan technique. This reveals that the crystal has a negative refractive index, which indicates the defocusing nature of the material. 相似文献
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Optical limiters relying on nonlinear absorption or nonlinear refraction are most effective against an incoming laser beam when the active material is thicker than one Rayleigh length. We have found that a variety of thick optical limiter configurations can be modelled by integrating the formulae for optical transmission by thin media, and that the results are exact to the first order in power or irradiance. The limiter behaviour saturates as the optical power increases. For the case of thick irradiance-dependent absorbers and an incident Gaussian beam model, we have also found that the predictions of a simple saturation formula for the optical transmittance agree well with the transmittance values computed using a numerical technique. Under certain conditions this saturation formula is also suitable for describing the transmission of nonlinear refractors, thereby providing a straight-forward technique for modelling limiters over a broad parameter range. 相似文献
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The third order nonlinear optical properties of Rhodamine6G (Rh6G) doped silica and polymeric samples have been investigated using single beam z-scan technique under excitation by the second harmonic of Nd:YAG laser beam (532 nm). The nonlinear refractive index, nonlinear absorption coefficient, real and imaginary parts of third order nonlinear susceptibility in the samples of silica and poly-methylmethacrylate (PMMA) matrices are measured. Thermal contribution to the nonlinear refractive index in case of undoped silica samples has been calculated in order to have better accuracy of the material response contribution to third order nonlinearity. The comparative study of the optical limiting performance of Rh6G doped silica and polymeric samples show that Rh6G doped silica is relatively superior for optical limiting applications. 相似文献
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N. Pinçon B. Palpant D. Prot E. Charron S. Debrus 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,19(3):395-402
We report a study on the third-order nonlinear optical properties of nanocomposite thin films composed of gold particles embedded
in a silica host matrix. Samples of various metal volume fractions, ranging from 8 to 35%, are synthesized by the sputtering
technique. Some of them are annealed. Nonlinear optical measurements, which are performed by using the z-scan technique, reveal both a very large nonlinear absorption and a weak nonlinear refraction close to the surface plasmon
resonance frequency of the particles. We especially study the effect of the metal concentration and the influence of thermal
treatment on the real and imaginary components of the third-order nonlinear susceptibility. Our results reveal that, as the
metal concentration reaches a few percent, the mutual electromagnetic interactions between particles greatly enlarge the nonlinear
optical response of the material and can not be neglected in the theoretical analysis. Moreover, the thermal treatment leads,
for a given concentration, to a significant increase of the nonlinear response, which is ascribed to a modification of the
material morphology. We finally point out that the material nonlinear properties are very sensitive to the incident wavelength
through the local field enhancement phenomenon.
Received 12 December 2001 相似文献
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WU Feng TIAN Wei MA i-Na CHEN Wen-Ju ZFANG Gui-Lan ZHAO Guo-Feng CAO Shi-Dong XIE Wei 《中国物理快报》2008,25(4):1461-1464
The optical nonlinear properties of CdSeS/ZnS quantum dots (QDs) areinvestigated by Z-scan technique using fundamental harmonic generation(1064nm) of mode-locked Nd:YAG laser for the first time. The experimental results show that two photon absorptions (TPA) occur at input intensity up to 12.5GW/cm2. CdSeS/ZnS QDs have an average TPA cross section of 13710GM and large nonlinear refractive index on order of 10-7esu. The large optical nonlinearities perhaps allow the CdSeS/ZnS QDs to be one kind of candidate material for bioimaging and fluorescence label, optical limiting and all-optical switching. 相似文献
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Exploring fundamental limits to terahertz generation in electrooptic materials: From bulk to nanolayers 总被引:1,自引:0,他引:1
We review the progress made by us on the exploration of the fundamental limits to terahertz (THz) generation from several semiconductor electrooptic materials. Through the measurements of the THz output versus the pump beam in terms of incident angle, polarization, azithumal angle, and pump intensity, we have demonstrated that we can precisely determine the contributions made by the optical rectification and photocurrent surge. When a material is pumped below its bandgap, optical rectification is always the mechanism for the THz generation. Above the bandgap, however, these two mechanisms often compete with each other, depending on the material characteristics and pump intensity. At a sufficiently high pump intensity, optical rectification usually becomes the dominant mechanism for a second-order nonlinear material. Our analysis indicates that second-order nonlinear coefficients are resonantly enhanced when a material is pumped above its bandgap. In such a case, the THz output power and normalized conversion efficiency can be dramatically increased. We have also illustrated that, for some materials, two-photon absorption can be one of the fundamental limits to the THz generation. 相似文献
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S. Manikandan T. C. Sabari Girisun R. Mohandoss S. Dhanuskodi S. Manivannan 《Optics and Spectroscopy》2014,117(3):469-473
The third-order nonlinear optical properties of solution-grown methyl-p-hydroxy benzoate (MHB) single crystals were studied by Z-scan technique using a He-Ne (632.8 nm, 30 mW) laser. From the closed aperture Z-scan data, the valley followed by peak on the normalized transmittance indicates the sign of the nonlinear refractive index is positive and shows a self focusing nature. From the open aperture Z-scan curve, it is found that the nonlinear absorption is due to saturation. The order of magnitude of third order susceptibility was estimated to be 10?6 esu. UV-Vis-NIR spectrum of MHB single crystal reveals a very low cutoff wavelength (310 nm) and transparency in the entire visible region. Also the material has direct allowed transition and it possesses a band gap of 3.7 eV. The dissipation factor is low and SHG efficiency is high. The higher magnitudes of second and third order NLO parameters make the material suitable for photonic applications like frequency conversion and eye/sensor protection. 相似文献
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An apt and a futuristic nonlinear optical material sodium tetraborate pentahydrate (STBPH) was synthesized and grown by the technique of slow evaporation. The structural parameters of the crystal was confirmed by single crystal XRD revealed rhombohedral crystal system. Crystal's broad optical transparency was revealed by UV–Vis absorption spectrum. From the absorption spectrum, theoretical calculations were made to determine absorption coefficient, band gap, Urbach energy and reflectance. The functional groups were identified by FT-IR and FT-Raman spectra. Vicker's microhardness measurement disclosed that the grown crystal belongs to soft material category. Photoluminescence (PL) spectral study of STBPH indicated violet and blue emission peaks respectively at 343.06 nm and at 453.11 nm, 490.19 nm. Dielectric studies reveal the dielectric nature of the grown crystal. TGA-DTA studies showed that the crystal holds good thermal stability. The third order nonlinearities of STBPH was investigated by Z-scan technique manifest its suitability in nonlinear optical applications. 相似文献