Mode Coupling of Whispering Gallery Modes through Organic Semiconductor Thin Films
Mode Coupling of Whispering Gallery Modes through Organic Semiconductor Thin Films
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DOI：
10.1021/acs.jpcc.1c02665
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发表时间：
2021-07
期刊：
影响因子：
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通讯作者：
Akihiro Kameda;S. Shimomoto;H. Tajima;J. Yamada;Tokuji Yokomatsu;K. Maenaka;T. Komino
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文献类型：
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作者：
Akihiro Kameda;S. Shimomoto;H. Tajima;J. Yamada;Tokuji Yokomatsu;K. Maenaka;T. Komino
研究了微盘谐振器回音壁模式的模式耦合距离。以有机半导体材料4，4 ′-双[（N-咔唑）苯乙烯基]联苯为原料，采用真空气相沉积和光刻技术，在不使用干法刻蚀的情况下，制备了厚度为115-230 nm，直径为15 ± 3 μm的微圆盘谐振器。微盘被二维地图案化以形成方形单元。使用这些正方形的微盘阵列，我们观察到周期性的尖峰的光致发光光谱。这种光谱变窄是WGM共振放大自发辐射的结果。此外，当两个相邻微片之间的距离小于8 ± 1 μm时，观察到了由WGM模式耦合产生的精细结构。该距离比通过在传统WGM谐振器中使用的方法即倏逝波的重叠获得的模式耦合距离长1或2个数量级。我们认为，远程模式耦合起源于多重反射的有机薄膜上的偏移区域的微盘之间的有机薄膜区域起着模式耦合器的作用，在结合的WGM模式，站在微盘。
The mode coupling distance for the whispering gallery modes (WGMs) of microdisk resonators was investigated. Microdisk resonators with thicknesses in the 115–230 nm range and diameters of 15 ± 3 μm were fabricated from an organic semiconductor material, 4,4′-bis[(N-carbazole)styryl]biphenyl, via vacuum vapor deposition and photolithography without using a dry etching process. The microdisks were patterned two-dimensionally to form square-type unit cells. Using these square-type microdisk arrays, we observed periodic sharp peaks in the photoluminescence spectra. This spectral narrowing was the result of amplified spontaneous emission with a WGM resonance. Furthermore, fine structures from the mode coupling of the WGMs were observed when the distance between two adjacent microdisks was less than 8 ± 1 μm. This distance is 1 or 2 orders of magnitude longer than the mode coupling distance obtained through overlapping of evanescent waves, which is the method used in conventional WGM resonators. We consider that the long-range mode coupling originates from multiple reflections in the organic thin films on an offset area of the microdisks; an organic thin film area between the microdisks plays the role of a mode coupler in combining the WGM modes that are standing in the microdisks.