Optical dielectric function of gold
Optical dielectric function of gold
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DOI：
10.1103/physrevb.86.235147
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发表时间：
2012-12-28
影响因子：
3.7
通讯作者：
Raschke, Markus B.
中科院分区：
文献类型：
--
作者：
Olmon, Robert L.;Slovick, Brian;Raschke, Markus B.
在金属光学中，金具有特殊的地位，因为它在光电和纳米光学器件中的实际重要性，以及它作为研究电磁场与金属相互作用的基本电子激发的模型系统的作用。然而，在文献中发现，描述金光学响应的介电函数的频率依赖性很大程度上不一致。我们对蒸发金、模板剥离金和单晶金进行了精确的光谱椭偏测量，以确定在300 nm至25 μ m （0.05-4.14 eV）宽光谱范围内的光学介电函数，具有高光谱分辨率。我们将数据拟合到Drude自由电子模型，电子弛豫时间tau(D) = 14 +/- 3 fs，等离子体能量h ω (p) = 8.45 eV。我们发现，与文献中报道的数值范围相比，不同类型样品的介电函数的变化很小。然而，我们的值与过去六十年来以前的测量集合的总平均值相当。这表明，尽管一些变化可以归因于表面形态，但过去使用不同方法的测量似乎受到系统误差的困扰，而不是以前假设的那样。DOI: 10.1103 / PhysRevB.86.235147
In metal optics gold assumes a special status because of its practical importance in optoelectronic and nano-optical devices, and its role as a model system for the study of the elementary electronic excitations that underlie the interaction of electromagnetic fields with metals. However, largely inconsistent values for the frequency dependence of the dielectric function describing the optical response of gold are found in the literature. We performed precise spectroscopic ellipsometry measurements on evaporated gold, template-stripped gold, and single-crystal gold to determine the optical dielectric function across a broad spectral range from 300 nm to 25 mu m (0.05-4.14 eV) with high spectral resolution. We fit the data to the Drude free-electron model, with an electron relaxation time tau(D) = 14 +/- 3 fs and plasma energy h omega(p) = 8.45 eV. We find that the variation in dielectric functions for the different types of samples is small compared to the range of values reported in the literature. Our values, however, are comparable to the aggregate mean of the collection of previous measurements from over the past six decades. This suggests that although some variation can be attributed to surface morphology, the past measurements using different approaches seem to have been plagued more by systematic errors than previously assumed. DOI:10.1103/PhysRevB.86.235147