1. Fano-resonant ultrathin film optical coatings
- Author
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Jihua Zhang, Andrew Lininger, Sohail A. Jalil, Theodore Letsou, James Rutledge, Nathaniel Hoffman, Mohamed ElKabbash, Chun-Hao Fann, Giuseppe Strangi, Chunlei Guo, and Michael Hinczewski
- Subjects
Materials science ,Optical instrument ,Biomedical Engineering ,Physics::Optics ,Bioengineering ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,law.invention ,law ,Photovoltaics ,General Materials Science ,Electrical and Electronic Engineering ,business.industry ,Photovoltaic system ,Fano resonance ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Solar energy ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Optical coating ,Optoelectronics ,Photonics ,0210 nano-technology ,business ,Beam splitter - Abstract
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 (~30 °C), which could lead to a six-fold increase in the photovoltaic cell lifetime. A thin-film optical coating exhibits Fano resonance showing promising applications in structural colouring of transparent objects and hybrid thermal and photovoltaic power generation.
- Published
- 2021