共查询到18条相似文献,搜索用时 312 毫秒
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采用共混法以聚硅氧烷微球作为光散射剂,聚甲基丙烯酸甲酯为基材制备光散射材料.研究了聚硅氧烷微球的粒径与浓度对光散射材料总光透过率与扩散率的影响并与理论模拟值进行了对比分析.研究结果表明,聚硅氧烷微球与聚甲基丙烯酸甲酯折射率匹配良好,较好地解决了光散射材料透光率与扩散率之间的矛盾,实现了高透射与高雾度的双重要求.当微球粒径为5μm,填充浓度为0.6wt%时,厚度为1mm的光散射材料总光透过率为88.5%,扩散率为89.5%.可见光波段总光透过率基本不受光源波长变化影响.选取合适粒径,扩散率随光源波长变化也可降至最低,有效避免了波长色散现象.实验数据与理论模拟结果符合良好. 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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本文采用三维时域有限差分法(FDTD)和Maxwell应力张量法建立了单光镊在焦点附近俘获球形微粒的光阱力模型,采用基于球矢量波函数(VSWF)的五阶高斯光源作为仿真光源,得到了准确的光场传播.讨论了光源的波长、束腰、偏振态和微球的半径、折射率对光阱力的影响,分析了在单光镊俘获微球时,邻近微球对光阱力的影响.特别研究了光源的偏振态对微球所受光阱力的作用效果,仿真结果表明圆偏振光比线偏振光对微球的俘获力更大;被光镊稳定俘获的微球,会受到邻近微球干扰,失去平衡状态,改变光源的偏振态可以改变微球的受力状态.
关键词:
光镊
光阱力
介质微球
时域有限差分法(FDTD) 相似文献
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以超连续谱激光器作为捕获光源,首次提出并搭建了超连续谱双光束光纤光阱实验系统,实现了聚苯乙烯微球的捕获和操控。通过改变光纤端面间隔和调整捕获光功率的方式精确控制微球的位置,采用CCD图像分析方法实现了微球位置的精确测量。对微球受限布朗运动下的位置变化进行傅里叶变换,计算得到功率谱,与理论功率谱函数拟合后求出了其光阱刚度。结果表明,捕获光束的功率为28 mW时,光阱刚度达到1.3×10-6N/m,高于相同实验条件下单波长光纤光阱的刚度。与传统采用单色光作为捕获光源的光镊系统不同,超连续谱双光束光阱系统利用其宽谱优势,通过研究被捕获微粒的散射光谱信息可获取其尺寸、折射率等物理特征参数。 相似文献
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基于Mie散射理论,利用一次聚生角毛藻赤潮生消过程的水体吸收光谱数据,反演了藻细胞的折射率虚部,开展了细胞平均吸收效率因子(Qa)、后向散射效率因子(Qbb)和散射相函数的光谱模拟与分析。研究发现:(1)均匀球模型(Mie理论)能较好地重现聚生角毛藻的吸收光谱特征,Qa平均相对误差在11%以内。(2)Qbb受吸收影响,这一方面体现于Qbb在400~700nm波段的光谱变化,即吸收极大值的波长处Qbb取极小值;也体现在整个赤潮生消过程中,赤潮爆发前Qbb大,赤潮爆发后Qbb变小。(3)总散射与粒径参数(表征粒径相对于波长的大小)成正比,受吸收的影响小;总散射与角度散射强度反比于波长。 相似文献
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为增强晶体硅太阳电池的光利用效率,提高光电转换效率,研究了金属银纳米颗粒的光学散射性质.基于银纳米粒子表面等离子激元效应和MIE散射理论,采用Matlab数值计算,理论分析了不同银纳米颗粒尺寸和银粒子分布密度对太阳光谱各波长的散射特性.获得了实现高的光透过率所需最佳银纳米颗粒半径范围,研究发现随着银纳米颗粒半径增加,偶极峰红移、高极峰逐渐出现.定量地给出了最佳颗粒分布密度随银粒子半径的变化规律,建立了计算减反射膜透射率的理论方法,找到了银纳米颗粒光学透过率的简单函数表达式,能为实验研究提供理论指导.
关键词:
银纳米颗粒
透过率
MIE理论
太阳电池 相似文献
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基于Stockes矢量,通过测量以线偏振光和圆偏振光入射时脂肪乳剂后向散射光的偏振度,研究了532 nm、650 nm和780 nm三个波长的光与散射粒子粒径为325 nm的脂肪乳剂溶液作用后,其后向散射光的偏振度特性.研究结果表明,对于入射线偏振光,780 nm波长后向散射光中的线偏振光成分多于圆偏振光成分,而532 nm波长则相反;对于入射圆偏振光,三个波长后向散射光中的圆偏振光成分均多于线偏振光成分;532 nm波长的总偏振度高于650 nm和780 nm两个波长各自的总偏振度;线偏振光的保偏性优于圆偏振光的保偏性,但偏振光在散射介质中的穿透深度较小.因此,后向散射成像技术适用于物体表层成像,而且选择波长略大于粒径的线偏振光可以提高成像质量. 相似文献
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基于Stockes矢量,通过测量以线偏振光和圆偏振光入射时脂肪乳剂后向散射光的偏振度,研究了532nm、650nm和780nm三个波长的光与散射粒子粒径为325nm的脂肪乳剂溶液作用后,其后向散射光的偏振度特性.研究结果表明,对于入射线偏振光,780nm波长后向散射光中的线偏振光成分多于圆偏振光成分,而532nm波长则相反;对于入射圆偏振光,三个波长后向散射光中的圆偏振光成分均多于线偏振光成分;532nm波长的总偏振度高于650nm和780nm两个波长各自的总偏振度;线偏振光的保偏性优于圆偏振光的保偏性,但偏振光在散射介质中的穿透深度较小.因此,后向散射成像技术适用于物体表层成像,而且选择波长略大于粒径的线偏振光可以提高成像质量. 相似文献
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This paper characterizes holographic scattering and demonstrates its application in determining the kinetic parameters in
materials with high transmittance and strong holographic scattering like phenanthrenequinone doped poly (methyl methacrylate)
(PQ-PMMA). We define a polymerization rate parameter which can be determined by the temporal evolution of the scattering losses.
Two basic kinetic parameters, quantum yield and molar-absorption coefficient, are obtained by nonlinear fitting the curve
of the polymerization rate parameter as a function of the thickness, which are 1.9×10−6 mol/einstein and 2.1×104 cm2/mol for a wavelength of 532 nm respectively. These results improve the understanding of photochemical behaviors and allow
us to describe the grating formation in the photopolymer reasonably. 相似文献
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The visibility in a fire scene decreases because of the existence of smoke produced by the flammable materials. With the growth of smoke concentration, the relationship between light and smoke becomes complicated due to the multiple scattering. In this paper, the radiative transfer equation (RTE) that considers the multiple scattering was applied to calculate the light transmission in a smoke layer. As input parameters of RTE, the single scattering albedo, asymmetry parameter and extinction cross section of single smoke agglomerate were calculated by the discrete dipole approximation (DDA) method. The effects of smoke agglomerate diameter, number density of smoke layer, and the incident light wavelength were considered. The results show that the light transmitted flux decreases with the growth of smoke diameter and number density, and increases with the growth of wavelength. The smoke diameter is dominant among the three parameters, and the light transmitted flux tends to be stable when the wavelength reaches a certain value. 相似文献
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We report on linear transmittance and reflectance as well as on third-harmonic generation in photonic crystal alloys formed by various compositions of polystyrene and poly (methyl methacrylate) colloidal spheres of the same size. These photonic crystal alloys are structurally ordered but contain refractive-index disorder and thus provide a random variation of scattering potential. The stopgap shows a monotonic shift in wavelength as a function of composition that can be fitted by assuming an effective dielectric constant for the colloidal spheres. In each alloy a dramatic enhancement of third-harmonic generation is observed, always on the short-wavelength side of the stopgap. 相似文献
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Optical characteristics of silver-doped polarizing glass 总被引:1,自引:0,他引:1
According to the theory of scattering and absorption of light, an anisotropic Ag colloid particle, which is small compared with the wavelength of the incident light, absorbs light differently in different directions. The underlying mechanism is regarded as electron plasma resonance. The optical anisotropy of a single Ag particle or of a group of the same particles has been analyzed. An equation for estimating the distribution of the particle shapes in space is proposed. Based on this equation and the work of other researchers, a program was designed to calculate the major principal transmittance and the minor principal transmittance of Ag-doped polarizing glass. The results show that the polarizing property of glass with particles with different aspect ratios is better than that of glass with identical particles. Also, the effective wavelength range is different if the particles' aspect ratios change, and this range tends to narrow as the parameter R (the rate of change of the aspect ratio) is increased. 相似文献