Fano-resonant ultrathin film optical coatings
Fano-resonant ultrathin film optical coatings
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DOI：
10.1038/s41565-020-00841-9
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发表时间：
2021-02-04
影响因子：
38.3
通讯作者：
Guo, Chunlei
中科院分区：
文献类型：
--
作者：
ElKabbash, Mohamed;Letsou, Theodore;Guo, Chunlei
光学薄膜是几乎所有光学仪器的组成部分。然而，尽管是一项有百年历史的技术，但光学涂层类型却屈指可数。在这里，我们介绍了一种类型的光学薄膜，表现出光子Fano共振，或Fano共振光学涂层（FROC）。我们扩展耦合机械振荡器的Fano谐振薄膜纳米腔的描述。使用FROCs的厚度在300 nm的顺序，我们实验获得窄带反射类似于低折射率对比度的介质布拉格镜，并实现了控制的反射彩虹色。我们观察到，半透明的FROCs可以透射和反射与分束器滤光片相同的颜色，这是通过传统光学涂层无法实现的特性。最后，FROCs可以在光谱和空间上分离太阳光谱的热和光伏带，为光伏发电中的可调度性问题提供了一种可能的解决方案，即无法按需调度太阳能。我们的太阳能热装置的发电量高达50%，光伏电池温度低（接近30摄氏度），这可能导致光伏电池寿命增加六倍。
Optical coatings are integral components of virtually every optical instrument. However, despite being a century-old technology, there are only a handful of optical coating types. Here, we introduce a type of optical coatings that exhibit photonic Fano resonance, or a Fano-resonant optical coating (FROC). We expand the coupled mechanical oscillator description of Fano resonance to thin-film nanocavities. Using FROCs with thicknesses in the order of 300 nm, we experimentally obtained narrowband reflection akin to low-index-contrast dielectric Bragg mirrors and achieved control over the reflection iridescence. We observed that semi-transparent FROCs can transmit and reflect the same colour as a beam splitter filter, a property that cannot be realized through conventional optical coatings. Finally, FROCs can spectrally and spatially separate the thermal and photovoltaic bands of the solar spectrum, presenting a possible solution to the dispatchability problem in photovoltaics, that is, the inability to dispatch solar energy on demand. Our solar thermal device exhibited power generation of up to 50% and low photovoltaic cell temperatures (similar to 30 degrees C), which could lead to a six-fold increase in the photovoltaic cell lifetime.