Spectroscopic ellipsometer for the infrared

将获得红外光谱范围的光谱椭偏仪。与已有的椭偏仪一起，这将被用来研究从远红外(0.04 eV)到深紫外光(8.50 eV)的宽光谱范围内的材料和系统的光学性质，特别是介电函数。对红外光谱区介电函数的激发，通常是声子模、自由载流子和电子跃迁，将通过线形分析来确定，并研究它们之间的相互影响。特别感兴趣的是光学各向异性材料，特别是具有单斜晶系或三斜晶系结构的材料。由于至少有两个晶轴不是相互垂直的，一些物理量，如介电函数张量或有效质量张量，具有不消失的非对角元素，因此可能会出现新的效应，如违反Lo-to规则或形成奇异光轴。这些不消失的侧对角元对(块体)材料和人造光子系统的光学响应的影响以及潜在的物理过程将被研究。这将首先通过实验确定介电张量，并通过拟合理论线形模型以及更一般的光学各向异性系统理论来确定介电张量和互补性。

A spectroscopic ellipsometer for the infrared spectral range is to be acquired. In conjunction with the ellipsometers already available, this will be used to study the optical properties, in particular the dielectric function, of materials and systems in a wide spectral range from the far infrared (0.04 eV) to the deep ultraviolet spectral range (8.50 eV). The excitations contributing to the dielectric function in the infrared spectral region, typically phonon modes, free charge carriers and also electronic transitions, will be determined by line shape analysis and investigated for their mutual influence. Of particular interest are optically anisotropic materials, especially with a monoclinic or triclinic crystal structure. Since at least two crystal axes are not orthogonal to each other, some physical quantities, such as the tensor of the dielectric function or the effective mass tensor, have non-vanishing off-diagonal elements, so that new effects can occur, such as the violation of the LO-TO rule or the formation of singular optical axes. The influence of these non-vanishing side diagonal elements on the optical response of (bulk) materials and also artificial photonic systems as well as the underlying physical processes will be investigated. This will be done first of all by experimental determination of the dielectric tensor and complementary by fitting to theoretical line shape models as well as more general theories of optically anisotropic systems.