Determination of the complex dielectric tensor of triclinic crystals: theory
Determination of the complex dielectric tensor of triclinic crystals: theory
复制标题
三斜晶体复介电张量的测定：理论
DOI：
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发表时间：
1983
期刊：
影响因子：
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通讯作者：
J. Aronson
中科院分区：
文献类型：
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作者：
A. Emslie;J. Aronson
对于晶轴相对于立方体边缘的任何所需取向，从三斜晶体切割而来的立方体的三个面上的垂直入射反射率的理论表达式得到了推导。反射率用晶体的复介电张量的分量来表示，该复介电张量涉及立方轴。文中还给出了一个合适的色散公式，其中介电张量的每个分量，称为固定的立方轴，是所有晶体振荡器的贡献之和，每个振荡器的贡献乘以振荡器轴相对于立方体轴的方向余弦的乘积。基于振子参数和方向余弦的变化，可以使用最小二乘拟合法在较宽的频率范围内获得测量和计算的反射率的最佳匹配，从而确定介电张量作为频率的函数。
Theoretical expressions are derived for normal-incidence reflectances at three faces of a cube, cut from a triclinic crystal, for any desired orientation of crystallographic axes relative to the cube edges. The reflectances are expressed in terms of the components of the complex dielectric tensor of the crystal referred to the cube axes. Also presented is a suitable dispersion formula in which each component of the dielectric tensor, referred to the fixed cube axes, is given as a sum of the contributions of all crystal oscillators, each multiplied by products of the direction cosines of the oscillator axis relative to the cube axes. A least-squares-fitting procedure, based on the variation of the oscillator parameters and the direction cosines, can be used to obtain the best match of the measured and calculated reflectances, over a wide frequency range, and thereby to determine the dielectric tensor as a function of frequency.