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.
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The raw numerical data for the figures in the manuscript, as well as the code on the thin-film coupled oscillator theory, are available via GitHub at https://github.com/hincz-lab/Fano-resonant-ultrathin-film-optical-coatings-FROC.
Limonov, M. F., Rybin, M. V., Poddubny, A. N. & Kivshar, Y. S. Fano resonances in photonics. Nat. Photonics 11, 543–554 (2017).
Miroshnichenko, A. E. et al. Fano resonances: a discovery that was not made 100 years ago. Opt. Photonics News 19, 48–48 (2008).
Giannini, V., Francescato, Y., Amrania, H., Phillips, C. C. & Maier, S. A. Fano resonances in nanoscale plasmonic systems: a parameter-free modeling approach. Nano Lett. 11, 2835–2840 (2011).
Mukherjee, S. et al. Fanoshells: nanoparticles with built-in Fano resonances. Nano Lett. 10, 2694–2701 (2010).
Zhang, S., Bao, K., Halas, N. J., Xu, H. & Nordlander, P. Substrate-induced Fano resonances of a plasmonic nanocube: a route to increased-sensitivity localized surface plasmon resonance sensors revealed. Nano Lett. 11, 1657–1663 (2011).
Luk’yanchuk, B. et al. The Fano resonance in plasmonic nanostructures and metamaterials. Nat. Mater. 9, 707–715 (2010).
Fan, J. A. et al. Self-assembled plasmonic nanoparticle clusters. Science 328, 1135 (2010).
Verellen, N. et al. Fano resonances in individual coherent plasmonic nanocavities. Nano Lett. 9, 1663–1667 (2009).
Fedotov, V. A., Rose, M., Prosvirnin, S. L., Papasimakis, N. & Zheludev, N. I. Sharp trapped-mode resonances in planar metamaterials with a broken structural symmetry. Phys. Rev. Lett. 99, 147401 (2007).
Yang, Y., Kravchenko, I. I., Briggs, D. P. & Valentine, J. All-dielectric metasurface analogue of electromagnetically induced transparency. Nat. Commun. 5, 5753 (2014).
Shen, Y. et al. Structural colors from Fano resonances. ACS Photonics 2, 27–32 (2015).
Khurgin, J. B. Slow light in various media: a tutorial. Adv. Opt. Photon. 2, 287–318 (2010).
Miroshnichenko, A. E., Flach, S. & Kivshar, Y. S. Fano resonances in nanoscale structures. Rev. Mod. Phys. 82, 2257–2298 (2010).
Ruan, B. et al. Ultrasensitive terahertz biosensors based on Fano resonance of a graphene/waveguide hybrid structure. Sensors 17, 1924 (2017).
Wu, C. et al. Fano-resonant asymmetric metamaterials for ultrasensitive spectroscopy and identification of molecular monolayers. Nat. Mater. 11, 69–75 (2011).
Sounas, D. L. & Alù, A. Fundamental bounds on the operation of Fano nonlinear isolators. Phys. Rev. B 97, 115431 (2018).
Cordaro, A. et al. High-index dielectric metasurfaces performing mathematical operations. Nano Lett. 19, 8418–8423 (2019).
Sonnefraud, Y. et al. Experimental realization of subradiant, superradiant, and Fano resonances in ring/disk plasmonic nanocavities. ACS Nano 4, 1664–1670 (2010).
Liu, N. et al. Plasmonic analogue of electromagnetically induced transparency at the Drude damping limit. Nat. Mater. 8, 758–762 (2009).
Macleod, H. A. Thin Film Optical Filters, 4th edn (Adam Hilger, 1986).
Gallais, L. & Commandré, M. Laser-induced damage thresholds of bulk and coating optical materials at 1030 nm, 500 fs. Appl. Opt. 53, A186–A196 (2014).
Anjum, F., Fryauf, D. M., Ahmad, R., Phillips, A. C. & Kobayashi, N. P. Improving silver mirrors with aluminum oxynitride protection layers: variation in refractive index with controlled oxygen content by radiofrequency magnetron sputtering. IEEE Spect. 26, 34–35 (2018).
Tannas, L. E. Flat-panel displays displace large, heavy, power-hungry CRTs. IEEE Spectr. 26, 34–35 (1989).
Hornbeck, L. J. Digital light processing for high-brightness high-resolution applications. In Proc. SPIE 3013, Projection Displays III (SPIE, 1997).
Dobrowolski, J. A., Ho, F. C. & Waldorf, A. Research on thin film anticounterfeiting coatings at the National Research Council of Canada. Appl. Opt. 28, 2702–2717 (1989).
Granqvist, C. G. & Hjortsberg, A. Surfaces for radiative cooling: silicon monoxide films on aluminum. Appl. Phys. Lett. 36, 139–141 (1980).
Raman, A. P., Anoma, M. A., Zhu, L., Rephaeli, E. & Fan, S. Passive radiative cooling below ambient air temperature under direct sunlight. Nature 515, 540–544 (2014).
Chen, Z., Zhu, L., Raman, A. & Fan, S. Radiative cooling to deep sub-freezing temperatures through a 24-h day–night cycle. Nat. Commun. 7, 13729 (2016).
Chen, D. Anti-reflection (AR) coatings made by sol–gel processes: a review. Sol. Energy Mater. Sol. Cells 68, 313–336 (2001).
Li, Z., Butun, S. & Aydin, K. Large-area, lithography-free super absorbers and color filters at visible frequencies using ultrathin metallic films. ACS Photonics 2, 183–188 (2015).
ElKabbash, M., Iram, S., Letsou, T., Hinczewski, M. & Strangi, G. Designer perfect light absorption using ultrathin lossless dielectrics on absorptive substrates. Adv. Opt. Mater. 6, 1800672 (2018).
Kats, M. A., Blanchard, R., Genevet, P. & Capasso, F. Nanometre optical coatings based on strong interference effects in highly absorbing media. Nat. Mater. 12, 20–24 (2012).
ElKabbash, M. et al. Iridescence-free and narrowband perfect light absorption in critically coupled metal high-index dielectric cavities. Opt. Lett. 42, 3598–3601 (2017).
Svensson, J. S. E. M. & Granqvist, C. G. Electrochromic coatings for ‘smart windows’. Sol. Energy Mater. 12, 391–402 (1985).
Thielsch, R.in Optical Interference Coatings (eds Kaiser, N. & Pulker, H. K.) 257–279 (Springer, 2003).
Optical Thin Films and Coatings, From Materials to Applications 2nd edn (Elsevier, 2013).
Fan, S. Thermal photonics and energy applications. Joule 1, 264–273 (2017).
Fann, C.-H. et al. Broadband infrared plasmonic metamaterial absorber with multipronged absorption mechanisms. Opt. Express 27, 27917–27926 (2019).
ElKabbash, M. et al. Hydrogen sensing using thin-film perfect light absorber. ACS Photonics 6, 1889–1894 (2019).
Sreekanth, K. V. et al. Generalized Brewster angle effect in thin-film optical absorbers and its application for graphene hydrogen sensing. ACS Photonics https://doi.org/10.1021/acsphotonics.9b00564 (2019).
Gallinet, B. in Fano Resonances in Optics and Microwaves (eds Kamenetskii, E. et al.) 109–136 (Springer, 2018).
Joe, Y. S., Satanin, A. M. & Kim, C. S. Classical analogy of Fano resonances. Phys. Scr. 74, 259–266 (2006).
Ismail, N., Kores, C. C., Geskus, D. & Pollnau, M. Fabry-Pérot resonator: spectral line shapes, generic and related Airy distributions, linewidths, finesses, and performance at low or frequency-dependent reflectivity. Opt. Express 24, 16366–16389 (2016).
Vorobyev, A. Y. & Guo, C. Colorizing metals with femtosecond laser pulses. Appl. Phys. Lett. 92, 041914 (2008).
Fu, S. et al. Review of recent progress on single-frequency fiber lasers [Invited]. J. Opt. Soc. Am. B 34, A49–A62 (2017).
Lee, K.-T., Ji, C., Banerjee, D. & Guo, L. J. Angular- and polarization-independent structural colors based on 1D photonic crystals. Laser Photon. Rev. 9, 354–362 (2015).
Branz, H. M., Regan, W., Gerst, K. J., Borak, J. B. & Santori, E. A. Hybrid solar converters for maximum exergy and inexpensive dispatchable electricity. Energy Environ. Sci. 8, 3083–3091 (2015).
Mojiri, A., Taylor, R., Thomsen, E. & Rosengarten, G. Spectral beam splitting for efficient conversion of solar energy—a review. Renew. Sustain. Energy Rev. 28, 654–663 (2013).
Vossier, A. et al. Performance bounds and perspective for hybrid solar photovoltaic/thermal electricity-generation strategies. Sustain. Energy Fuels 2, 2060–2067 (2018).
Maghanga, C. M., Niklasson, G. A., Granqvist, C. G. & Mwamburi, M. Spectrally selective reflector surfaces for heat reduction in concentrator solar cells: modeling and applications of TiO2:Nb-based thin films. Appl. Opt. 50, 3296–3302 (2011).
Wang, Y., Liu, H. & Zhu, J. Solar thermophotovoltaics: progress, challenges, and opportunities. APL Mater. 7, 080906 (2019).
Sun, X., Sun, Y., Zhou, Z., Muhammad, A. & Bermel, P. Radiative sky cooling: fundamental physics, materials, structures, and applications. Nanophotonics 6, 997–1015 (2017).
Singh, S. C. et al. Solar-trackable super-wicking black metal panel for photothermal water sanitation. Nat. Sustain. https://doi.org/10.1038/s41893-020-0566-x (2020).
Denholm, D., O‘Connell, M., Brinkman, G. & Jorgenson, J. Overgeneration from Solar Energy in California: A Field Guide to the Duck Chart (National Renewable Energy Laboratory, 2015).
Sreekanth, K. V. et al. Phase-change-material-based low-loss visible-frequency hyperbolic metamaterials for ultrasensitive label-free biosensing. Adv. Opt. Mater. 7, 1900081 (2019).
Zhan, Z. et al. Enhancing thermoelectric output power via radiative cooling with nanoporous alumina. Nano Energy 65, 104060 (2019).
Kraemer, D. et al. High-performance flat-panel solar thermoelectric generators with high thermal concentration. Nat. Mater. 10, 532–538 (2011).
Jalil, S. A. et al. Spectral absorption control of femtosecond laser-treated metals and application in solar-thermal devices. Light. Sci. Appl. 9, 14 (2020).
Xu, Y. & Miroshnichenko, A. E. Reconfigurable nonreciprocity with a nonlinear Fano diode. Phys. Rev. B 89, 134306 (2014).
Chen, Z. et al. Graphene controlled Brewster angle device for ultra broadband terahertz modulation. Nat. Commun. 9, 4909 (2018).
Mathematica v.12 (Wolfram, 2019).
Lumerical (Ansys, Inc., 2020).
Bermel, P. et al. Design and global optimization of high-efficiency thermophotovoltaic systems. Opt. Express 18, A314–A334 (2010).
We thank M. Mann and J. A. Fenster for their assistance in taking high-quality photos. We thank H. M. Cao for providing assistance in schematics. M.E. acknowledges fruitful discussions with K. Singer. C.G. acknowledges the support of the Army Research Office, the National Science Foundation and AlchLight. G.S. and M.H. acknowledge the support of the National Science Foundation.
A patent application has been filed on the Fano resonance optical coating scheme in this work.
Peer review information Nature Nanotechnology thanks Koray Aydin and Jiming Bao for their contribution to the peer review of this work.
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ElKabbash, M., Letsou, T., Jalil, S.A. et al. Fano-resonant ultrathin film optical coatings. Nat. Nanotechnol. 16, 440–446 (2021). https://doi.org/10.1038/s41565-020-00841-9