Palermo Giovanna, Lininger Andrew, Guglielmelli Alexa, Ricciardi Loredana, Nicoletta Giuseppe, De Luca Antonio, Park Joon-Suh, Lim Soon Wei Daniel, Meretska Maryna L, Capasso Federico, Strangi Giuseppe
Department of Physics, NLHT-Lab, University of Calabria and CNR-NANOTEC Istituto di Nanotecnologia, 87036 Rende, Italy.
Department of Physics, Case Western Reserve University, 2076 Adelbert Road, Cleveland, Ohio 44106, United States.
ACS Nano. 2022 Oct 25;16(10):16539-16548. doi: 10.1021/acsnano.2c05887. Epub 2022 Oct 10.
Metasurfaces have been extensively engineered to produce a wide range of optical phenomena, allowing exceptional control over the propagation of light. However, they are generally designed as single-purpose devices without a modifiable postfabrication optical response, which can be a limitation to real-world applications. In this work, we report a nanostructured planar-fused silica metalens permeated with a nematic liquid crystal (NLC) and gold nanoparticle solution. The physical properties of embedded NLCs can be manipulated with the application of external stimuli, enabling reconfigurable optical metasurfaces. We report the all-optical, dynamic control of the metalens optical response resulting from thermoplasmonic-induced changes of the NLC solution associated with the nematic-isotropic phase transition. A continuous and reversible tuning of the metalens focal length is experimentally demonstrated, with a variation of 80 μm (0.16% of the 5 cm nominal focal length) along the optical axis. This is achieved without direct mechanical or electrical manipulation of the device. The reconfigurable properties are compared with corroborating numerical simulations of the focal length shift and exhibit close correspondence.
超表面已经经过广泛的设计，以产生各种光学现象，从而能够对光的传播进行卓越的控制。然而，它们通常被设计为单一用途的器件，没有可修改的制造后光学响应，这可能会限制其在实际应用中的使用。在这项工作中，我们报道了一种渗透有向列型液晶（NLC）和金纳米颗粒溶液的纳米结构平面熔融石英超透镜。通过施加外部刺激，可以操纵嵌入的NLC的物理性质，从而实现可重构的光学超表面。我们报道了由热等离子体诱导的与向列-各向同性相变相关的NLC溶液变化所导致的超透镜光学响应的全光动态控制。实验证明了超透镜焦距的连续且可逆调谐，沿光轴的变化为80μm（占5cm标称焦距 的0.16%）。这是在不对器件进行直接机械或电气操纵的情况下实现的。将可重构特性与焦距偏移的数值模拟结果进行了比较，两者表现出密切的对应关系。
