Walden Sarah L, Poudel Purushottam, Zou Chengjun, Tanaka Katsuya, Paul Pallabi, Szeghalmi Adriana, Siefke Thomas, Pertsch Thomas, Schacher Felix H, Staude Isabelle
Institute of Solid State Physics, Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 3, 07743 Jena, Germany.
Institute of Applied Physics, Abbe Center of Photonics, Friedrich Schiller University Jena, Albert-Einstein-Strasse 15, 07745 Jena, Germany.
ACS Nano. 2024 Feb 13;18(6):5079-5088. doi: 10.1021/acsnano.3c11760. Epub 2024 Jan 30.
For the realization of truly reconfigurable metasurface technologies, dynamic spatial tuning of the metasurface resonance is required. Here we report the use of organic photoswitches as a means for the light-induced spatial tuning of metasurface resonances. Coating of a dielectric metasurface, hosting high-quality-factor resonances, with a spiropyran (SPA)-containing polymer enabled dynamic resonance tuning up to 4 times the resonance full-width at half-maximum with arbitrary spatial precision. A major benefit of employing photoswitches is the broad toolbox of chromophores available and the unique optical properties of each. In particular, SPA and azobenzene (AZO) photoswitches can both be switched with UV light but exhibit opposite refractive index changes. When applied to the metasurface, SPA induced a red shift in the metasurface resonance with a figure of merit of 97 RIU, while AZO caused a blue shift in the resonance with an even greater sensitivity of 100 RIU. Critically, SPA and AZO can be individually recovered with red and blue light, respectively. To exploit this advantage, we coated a dielectric metasurface with spatially offset SPA- and AZO-containing polymers to demonstrate wavelength-dependent, spatially resolved control over the metasurface resonance tuning.
为了实现真正可重构的超表面技术，需要对超表面共振进行动态空间调谐。在此，我们报告了使用有机光开关作为对超表面共振进行光诱导空间调谐的一种手段。用含螺吡喃（SPA）的聚合物涂覆具有高品质因数共振的介质超表面，能够以任意空间精度将共振动态调谐至共振半高宽的4倍。采用光开关的一个主要优点是有可用的广泛发色团工具箱以及每个发色团独特的光学性质。特别是，SPA和偶氮苯（AZO）光开关都可以用紫外光切换，但表现出相反的折射率变化。当应用于超表面时，SPA使超表面共振发生红移，品质因数为97 RIU，而AZO使共振发生蓝移，灵敏度甚至更高，为100 RIU。至关重要的是，SPA和AZO可以分别用红光和蓝光单独恢复。为了利用这一优势，我们用空间偏移的含SPA和AZO的聚合物涂覆介质超表面，以展示对超表面共振调谐的波长依赖性、空间分辨控制。
