Spectral properties of La/B - based multilayer mirrors near the boron K absorption edge
Spectral properties of La/B - based multilayer mirrors near the boron K absorption edge
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DOI：
10.1364/oe.20.011778
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发表时间：
2012-05-21
期刊：
影响因子：
3.8
通讯作者：
Bijkerk, Fred
中科院分区：
文献类型：
--
作者：
Makhotkin, Igor A.;Zoethout, Erwin;Bijkerk, Fred
根据测量的 B 和 B4C 光学常数，研究了 La/B、La/B4C 和 LaN/B、LaN/B4C 多层反射镜在 6.5-6.9 nm 波长范围内的光谱特性。通过实验验证了测量和列表光学常数在多大程度上适用于这些短周期多层反射镜的反射率的模拟。将硼-K 吸收边周围不同波长值的测量最大反射率与模型系统的计算值进行比较。 La/B 和 La/B4C 的测量反射率分布在比根据测量的 B 和 B4C 光学常数计算预测的波长稍大的波长处显示出最大值。这是通过形成的硼-镧化合物对多层显示最大反射率的波长的影响来解释的。使用相同的硼原子散射因子可以准确描述LaN/B和LaN/B4C多层膜的最大反射率分布，表明LaN/B4C多层膜中的硼与LaN/B多层膜中的硼处于相似的化学状态。它还表明多层中 La 层的氮化防止了 La-B 化合物的形成。我们证明硼基光学器件的最佳波长约为 6.65 nm，并且取决于 B 化学态。最后，使用测量的 B 光学常数，我们能够计算多层膜的光谱响应，从而能够预测上述多层膜的最佳参数 (C) 2012 美国光学学会
The spectral properties of La/B, La/B4C, and LaN/B, LaN/B4C multilayer mirrors have been investigated in the 6.5-6.9 nm wavelength range based on measured B and B4C optical constants. Experimentally it is verified to what extent measured and tabulated optical constants are applicable for simulations of the reflectivity of these short period multilayer mirrors. The measured maximum reflectance at various wavelength values around the boron-K absorption edge is compared to calculated values from model systems. The measured reflectance profiles of La/B and La/B4C show a maximum at a slightly larger wavelength than calculations would predict based on the measured B and B4C optical constants. This is explained by the influence of a formed boron-lanthanum compound on the wavelength where the multilayer shows maximum reflectance. The maximum reflectance profiles of LaN/B and LaN/B4C multilayers can be described accurately by using the same boron atomic scattering factors, indicating boron in the LaN/B4C multilayer to be in a similar chemical state as boron in the LaN/B multilayer. It also indicates that nitridation of the La layer in the multilayer prevents the formation of La-B compounds. We show that the optimal wavelength for boron based optics is about 6.65 nm and depends on the B chemical state. Finally, using the measured B optical constants we are able to calculate the spectral response of the multilayers, enabling the prediction of the optimal parameters for the above mentioned multilayers (C) 2012 Optical Society of America