共查询到19条相似文献,搜索用时 46 毫秒
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在线性光学范畴内,人们已经通过亚波长尺度的超薄超构表面成功实现了对光的众多新颖特性的调控功能.其主要理念是通过对具有亚波长尺度且空间方向变化的超构功能基元进行特定的排列,从而实现对光的偏振、相位和振幅的有效控制.近来,超构表面上的非线性光学特性也引起了大家的广泛关注.在本综述中,我们对非线性光学超构表面的设计、超构功能单元的材料和对称性选择、非线性手性光学、非线性贝里几何相位和非线性波前整形等内容进行了总结;最后对非线性光学超构表面在调控光与物质的相互作用中面临的挑战和前景进行了展望. 相似文献
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被动光学限幅器的机制与研究进展 总被引:1,自引:0,他引:1
被动光学限幅器是利用介质的非线性光学性质实现对光的强度进行控制的器件,它在科研,军事和民用方面都具有广泛的应用,文章讨论了被动光学限幅器的反饱和吸收,双光子吸收,自由载流子吸收,非线性折射,光致散射和光折变机制,每种机制在光限幅器应用中的有效性及局限性,介绍了国内外研究状况及自己的工作;指出了今后被动光学限幅器研究的发展方向。 相似文献
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一个新的研究领域,表面非线性光谱学正在迅速发展。它起源于新发现的表面增强拉曼散射(SERS)与非线性光学现象的交叉,包括表面增强的二次谐波产生(SESHG),表面增强的双光子荧光,表面增强的超拉曼散射,四波混频及相干反斯托克斯拉曼散射等等。本文概述了这一发展中领域的实验结果、理论状况及可能的应用,对其特点(如高灵敏度、高分辨率等)及发展前景做了粗浅的分析和讨论。 相似文献
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以衍射理论为基础,建立了强非线性吸收下,非线性介质对高斯光束的衍射模型.数值计算表明,折射相移的增大使峰的透过率增强而谷的透过率趋于饱和;而吸收相移的增大使峰的透过率被抑制而谷的透过率增强.相移比值是决定谷-峰结构存在与否的关键.在一定的输入功率下,远场输出功率并不是完全随着非线性吸收系数的增大而增大.该理论的近似条件只要求是薄样品,具有更好的适用性. 相似文献
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Solid-state dye-doped polymers are an attractive alternative to the conventional liquid-dye solutions. The search for new materials which have potential application in optoelectronic devices has lead us to probe the organic dyes. The solid state being a better medium when compared to a liquid medium has lead to the incorporation of dyes in the polymer matrix. The study of nonlinear characteristics of dyes in polymeric media is essential for developing such potential application devices. In this paper, the third-order nonlinear optical properties of three dyes from the Triarylmethane family were measured in 1-Butanol and in dye-doped polymer films by the Z-scan technique using a cw diode-pumped Nd:YAG laser at 532 nm. The Z-scan technique has also been used to present the observation of a nonlinear refractive index resulting from the photochromism of one of the dyes. These materials exhibit a large negative optical nonlinearity resulting due to the thermal effect. The relative contributions from the nonlinear absorption (NLA) and nonlinear refraction (NLR) are dependent on the chemical structure and linear absorption of the dyes. The dyes exhibited a nonlinear refractive coefficient n 2, a nonlinear absorption coefficient β, and susceptibility x(3) on the order of 10?8 cm2/W, 10?4 cm/W, and 10?6 esu, respectively, in both liquid and solid media. The results show that these dyes have potential applications in nonlinear optics. 相似文献
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The optical nonlinearity of styryl7 dye in ethanol solution at different concentrations has been studied using pulsed Nd:YAG laser at 532 nm as the source of excitation. The optical responses were characterized by measuring the intensity dependent refractive index (n2) of the medium using the Z-scan technique. The open aperture Z-scan trace of the dye in solution displayed saturable absorption. The closed aperture Z-scan trace of the dye exhibited a negative nonlinearity. The styryl7 dye at 1 mM concentration exhibited nonlinear refractive co-efficient n2 = −1.24 × 10−8 cm2/W, nonlinear absorption coefficient β = − 3.9 × 10−4 cm/W and real and imaginary parts of third-order nonlinear optical susceptibility χ3 = 3.26 × 10−6 esu in ethanol. These results showed that the dye has potential application in nonlinear optics. 相似文献
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D. Cotter 《Optical and Quantum Electronics》1987,19(1):1-17
The article reviews the effects — both detrimental and potentially beneficial — of optical nonlinearity in fibres for telecommunications. 相似文献
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Fanjing Wang Wen XiaoFeng Pan Shuo LiuLin Cong Rui LiLu Rong Aga He 《Optics and Lasers in Engineering》2011,49(7):903-906
In this paper, an optical surface curvature measurement technique based on digital holography is proposed. Unlike the previous digital holographic methods, which only involve a small part of the measured data for parameter estimation, the proposed method adopts more of them using least square method. Hence, the analyzed result is not affected by data extraction direction and less sensitive to imperfect phase compensation. The proposed method is demonstrated with a sample of reflection mirror in laser resonator, and verified by comparing the measurement result with that of the white light interferometer. 相似文献
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The third-order optical nonlinearities of dimethyl sulfoxide(DMSO) are investigated using the optical Kerr effect(OKE) and Z-scan techniques with femtosecond pulses.We are able to fit the OKE signal theoretically by convolving the autocorrelation of the incident pulse intensity profile with the impulse responses of the samples,illustrating the instantaneous nonlinear response of DMSO.We verify that the purely electronic cloud distortion causes the observed signal for DMSO.The Z-scan technique is used to estimate the third-order susceptibility of DMSO,which is about a quarter of that for CS2 and mainly comes from the nonlinear refraction with an intensity of less than 140 GW/cm2. 相似文献
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The transition from a low density gas of excitons to an electron-hole plasma is connected with strong variations of the optical properties. In this contribution we investigate both the optical nonlinearities produced in CdS by an intense laser beam in the spectral region close to the absorption edge and at the position of the laser itself. In a second part it is shown that the nonlinearities at the photon energy of the incident laser may lead to absorptive and dispersive optical bistability. 相似文献
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Anatase phase TiO2 films have been grown on fused silica substrate by pulsed laser deposition technique at substrate temperature of 750 °C under the oxygen pressure of 5 Pa. From the transmission spectra, the optical band gap and linear refractive index of the TiO2 films were determined. The third-order optical nonlinearities of the films were measured by Z-scan method using a femtosecond laser (50 fs) at the wavelength of 800 nm. The real and imaginary parts of third-order nonlinear susceptibility χ(3) were determined to be −7.1 × 10−11esu and −4.42 × 10−12esu, respectively. The figure of merit, T, defined by T=βλ/n2, was calculated to be 0.8, which meets the requirement of all-optical switching devices. The results show that the anatase TiO2 films have great potential applications for nonlinear optical devices. 相似文献
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Third order nonlinear optical susceptibilities χ(3) of GaAs/Ga1?xAlAs superlattices have been predicted which are two orders of magnitude larger than those of bulk GaAs. This enhancement is due to the band nonparabolicity arising from the additional periodicity of the superlattice. These predictions, based on a tight-binding model of the superlattice dispersion, are here extended to the more realistic Kronig-Penney (KP) model. Corrections to tight-binding are non-negligible; however, enhancements of χ(3) are still large but reduced approximately 30%–50% over previous estimates. The KP model is also here applied to superlattices employing InSb as the quantum well material. Because of the smaller effective mass of InSb, and taking account of its bulk nonparabolicity, the minibands move to higher energy, enhancing the interwell overlap and increasing χ(3) by about one order of magnitude over that of bulk InSb. The role of the barrier material in this case is important and is discussed. The interplay between the bulk nonparabolicity and that arising from the superlattice is also addressed. 相似文献