共查询到20条相似文献,搜索用时 125 毫秒
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从麦克斯韦方程出发,可以得到超薄金属膜层光学常数n、k与其厚度有关系的理论依据。采用电阻热蒸发和电子束热蒸发的方法在K9玻璃基底上分别沉积了不同厚度的Cu膜、Cr膜、Ag膜,由椭偏法检测、Drude模型拟合,获得了不同厚度Cu膜、Cr膜、Ag膜光学常数n、k随波长λ的变化规律。超薄金属薄膜与块状金属的光学常数相差较大,随着薄膜厚度的增加,n、k值趋近于块状金属。通过对样品膜层吸收、色散特性的分析,发现连续金属薄膜在可见光波段对长波的吸收较大,而且相比于介质薄膜平均色散率高10mn~102nm量级。 相似文献
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研究了向列相液晶缺陷TiO2和SiO2交替的光学多层膜一维光子晶体透射谱偏振敏感特性。外电压下透射光谱测试和模拟结果显示,对于平行取向的向列相液晶,当自然光垂直入射时,禁带中两处出现e(TE模式)光和o光(TM模式)透射峰,具有偏振敏感性。随着电压增大,e光透射峰蓝移与o光透射峰合二为一,光谱可调谐范围分别为31和34nm;而对于取向混乱的向列相液晶,禁带中两处出现独立的透射峰,无偏振敏感性。随着电压增大峰位也蓝移,光谱可调谐范围分别为64和15nm。通过混乱取向液晶分子,可以使o光和e光有效折射率值相等,获得偏振不敏感特性。 相似文献
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在传统教学演示实验中,使用起偏器和检偏器演示光的偏振现象只能获得2个偏振片的相对偏振方向.当偏振方向平行时,透射光的强度最大;偏振方向垂直时,透射光的强度最小.借鉴矢量偏振光的性质,自制了径向偏振片代替起偏器,根据透射光的强度分布可以直接观察到光的偏振方向. 相似文献
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超薄金属膜在太赫兹波段的探测器、反射镜、波导器件以及太赫兹量子级联激光器中得到了广泛应用。超薄金属膜的光学常数不仅是这些器件设计中不可缺少的参数,而且是开发新型光电材料的一个重要依据。文章运用太赫兹差分时域光谱技术对超薄金属铬、镍和钛膜的光学特性研究,获得其在太赫兹波段的折射率和消光系数,并根据菲涅尔公式计算入射介质为高阻GaAs时,GaAs/Metal界面的反射谱,三种金属在0.3~1.5THz的波段范围内的平均反射率均超过80%。研究超薄金属膜在太赫兹波段的反射特性,为设计性能优良的太赫兹辐射源、探测器及太赫兹光学元件奠定基础。 相似文献
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本文利用向列相液晶层作为激光偏振调控单元,涂覆于垂直腔面发射激光器(VCSEL)表面,测量并分析了不同温度下VCSEL正交线偏振光的阈值电流、峰值光功率和I-P特性. 实验结果表明:温度为293 K时,涂覆液晶后激光偏振第一跳变点和第二跳变点之间的电流值ΔI增大了2.2 mA,比无液晶时增大1倍. 温度为313 K、注入电流为3 mA时,两种正交线偏振光的光功率差ΔP由133.6 μW增大到248.8 μW,进一步增加了线偏振光的各向异性. 表面液晶层的引入有效地扩大了VCSEL的正交线偏振态稳定范围和光功率差,为实现液晶VCSEL高温单偏振稳定的设计和器件制备提供了理论和实验基础.
关键词:
垂直腔面发射激光器
向列相液晶
偏振态 相似文献
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金属薄膜电阻特性与厚度测量 总被引:1,自引:0,他引:1
考察不同沉积时间的金属铝与铜的薄膜的沉积态,电阻变化与厚度,厚度测量采用实验室光学干涉和透过率对比方法.金相显微与铝铜电阻变化的测量表明,不连续薄膜与连续过渡之间,电阻显著变化处不同.铝膜电阻随时间变化过程开始时存在波动状态. 相似文献
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A transparent electromagnetic-shielding film based on one-dimensional metal–dielectric periodic structures 下载免费PDF全文
In this study, we designed and fabricated optical materials consisting of alternating ITO and Ag layers. This approach is considered to be a promising way to obtain a light-weight, ultrathin and transparent shielding medium, which not only transmits visible light but also inhibits the transmission of microwaves, despite the fact that the total thickness of the Ag film is much larger than the skin depth in the visible range and less than that in the microwave region. Theoretical results suggest that a high dielectric/metal thickness ratio can enhance the broadband and improve the transmittance in the optical range. Accordingly, the central wavelength was found to be red-shifted with increasing dielectric/metal thickness ratio. A physical mechanism behind the controlling transmission of visible light is also proposed. Meanwhile, the electromagnetic shielding effectiveness of the prepared structures was found to exceed 40 dB in the range from 0.1 GHz to 18 GHz, even reaching up to 70 dB at 0.1 GHz, which is far higher than that of a single ITO film of the same thickness. 相似文献
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基于表面等离子激元的新型超薄金属减色滤波器具有可靠、易制备、高透射率等诸多优点.本文对银、铜、铝、镍等不同金属材料的超薄一维光栅减色滤波器进行了系统研究.仿真获得了透射光谱,理论计算了对应透射光谱的色品坐标,并推导出了银、铜、铝三种材料透射率最低点波长与膜厚、周期关系的经验公式.仿真研究发现:除了镍的选波性较差外,银、铜、铝均表现出较好的、不同的滤波特性,其中银的滤波范围较广,而铜、铝则分别在长、短波段表现出较好的滤波性能.为了验证仿真结果,利用磁控溅射技术和聚焦离子束刻蚀技术进行了三种材料的一维光栅减色滤波器的制备实验,并在显微镜下观察滤波器的颜色效应,结果与理论仿真相符合.研究结果表明:不同金属材料在相同微结构下的颜色效应存在较大差异,可根据实际滤波需要,选择材料和微结构参数来获得最佳性价比的滤波器. 相似文献
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A dispersion compensation method is introduced to correct the distorted image passing through an ultrathin metal film.An LCD-CCD system is modeled by the back propagation network and used to evaluate the transmittance of the ultrathin metal film.Training samples for the network come from 729 images captured by shooting test patches,in which the RGB values are uniformity distributed between 0 and 255.The RGB value of the original image that will be distorted by the dispersion is first transformed by mapping from the LCD to the CCD,multiplied by the inverse matrix of the transmittance matrix,and finally transformed by mapping from the CCD to the LCD,then the corrected image is obtained.In order to verify the effectiveness of the proposed method,ultrathin aluminum films with different thicknesses are evaporated on glass substrates and laid between the CCD and LCD.Experimental results show that the proposed method compensates for the dispersion successfully. 相似文献
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A Fourier spectrometry method for measuring the thickness of thin and ultrathin films with the help of an additional peak that depends on the optical thickness of the deposited film and is situated outside the region of the central peak of the interferogram is proposed. The experiment demonstrates the necessity of considering the change in optical path in the substrate that is induced by the deposited film. 相似文献
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Application of longitudinal generalized magneto-optical ellipsometry in magnetic ultrathin films 下载免费PDF全文
The longitudinal generalized magneto-optical ellipsometry(GME) method is extended to the measurement of threelayer ultrathin magnetic films. In this work, the theory of the reflection matrix is introduced into the GME measurement to obtain the reflective matrix parameters of ultrathin multilayer magnetic films with different thicknesses. After that, a spectroscopic ellipsometry is used to determine the optical parameter and the thickness of every layer of these samples, then the magneto-optical coupling constant of the multilayer magnetic ultrathin film can be obtained. After measurements of a series of ultrathin Fe films, the results show that the magneto-optical coupling constant Q is independent of the thickness of the magnetic film. The magneto-optical Kerr rotations and ellipticity are measured to confirm the validity of this experiment. Combined with the optical constants and the Q constant, the Kerr rotations and ellipticity are calculated in theory. The results show that the theoretical curve fits very well with the experimental data. 相似文献
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The reflection of linearly polarized light from an ultrathin anisotropic dielectric film on isotropic absorbing substrate is investigated analytically in the long-wavelength limit. All analytical results are correlated with the numerical solution of the anisotropic reflection problem on the basis of rigorous electromagnetic theory. Simple analytical approach developed in this work not only gives a physical insight into the reflection problem but also provides a way of estimating the necessary experimental accuracy for optical diagnostics by reflection characteristics. It is shown that obtained expressions are of immediate interest for determining the parameters of anisotropic surface layers. Innovative possibilities for optical diagnostics of anisotropic properties of ultrathin dielectric layers upon absorbing materials are discussed. 相似文献
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Gramotnev DK 《Optics letters》1998,23(2):91-93
A strong maximum of absorption (as much as 100%) of bulk TM electromagnetic waves by an ultrathin film with imaginary dielectric permittivity is shown to exist at some optimal film thickness. This typical thickness is usually much smaller than the wavelength and the wave penetration depth in the material of the film. The absorptivity maximum increases and the typical thickness decreases with increasing dielectric permittivity of the layer. An optical analog of linear (liquid) friction is discussed. A frictional contact approximation for TM electromagnetic waves is analyzed, and relevant boundary conditions with an optical coefficient of friction are derived. 相似文献