Wide-range line shape control of Fano-like resonances in all-dielectric multilayer structures based on enhanced light absorption in photochromic waveguide layers
Wide-range line shape control of Fano-like resonances in all-dielectric multilayer structures based on enhanced light absorption in photochromic waveguide layers
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DOI：
10.1063/1.5131681
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发表时间：
2020-02
影响因子：
3.2
通讯作者：
Ken Motokura;Byungjun Kang;M. Fujii;D. Nesterenko;Z. Sekkat;S. Hayashi
中科院分区：
文献类型：
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作者：
Ken Motokura;Byungjun Kang;M. Fujii;D. Nesterenko;Z. Sekkat;S. Hayashi
我们已经成功地控制在一个宽范围内的全介质多层结构中的类Fano共振的紫外光照射的线形。已知由支持半漏导模的波导层、间隔层和支持平面波导模的另一波导层组成的多层结构由于半漏导模和平面波导模之间的耦合而在衰减的全反射光谱中表现出类Fano线形。使用光致变色层，即，掺杂螺吡喃分子的层作为波导层之一，我们通过改变紫外照射剂量来控制波导层中的光吸收量。我们证明了，线的形状变化显着取决于紫外线剂量，从电磁诱导的类吸收的电磁诱导的类吸收的线形（或反之亦然），通过Fano的类线形。我们还证明了在Fano共振多层结构中由UV照射引起的光致变色响应相对于在单个光致变色层中的光致变色响应增强了100倍。我们的电磁计算的基础上的分析表明，戏剧性的线形状的变化和增强的光致变色响应的光致变色波导层内的增强的局部电场结合光致介电常数的虚部的增加的后果。
We have succeeded in controlling the line shape of Fano-like resonances in all-dielectric multilayer structures in a wide range by UV light irradiation. Multilayer structures consisting of a waveguide layer supporting a half-leaky guided mode, a spacer layer, and another waveguide layer supporting a planar waveguide mode are known to exhibit Fano-like line shapes in attenuated total reflection spectra due to coupling between the half-leaky guided mode and the planar waveguide mode. Using a photochromic layer, i.e., a layer doped with spiropyran molecules, as one of the waveguide layers, we controlled the amount of light absorption in the waveguide layer by varying the UV irradiation dose. We demonstrated that the line shape changes dramatically depending on the UV dose, from the electromagnetically induced transparency-like to electromagnetically induced absorption-like line shape (or vice versa) passing through the Fano-like line shape. We also demonstrated that the photochromic response induced by UV irradiation in the Fano-resonant multilayer structure is enhanced by a factor of ∼100 relative to that in a single photochromic layer. Our analyses based on electromagnetic calculations suggest that the dramatic line shape change and the enhanced photochromic response are the consequences of enhanced local electric fields inside the photochromic waveguide layer combined with the photoinduced increase in the imaginary part of the dielectric constant.