Chiral Opto‐Fluidics and Plasmonic Nanostructures as a Functional Nanosystem for Manipulating Surface Deformations

Abstract

Photothermal conversion of energy in plasmonic nanostructures brought a new fascinating field of plasmon‐induced optofluidics to life. Notably, the heat generation by plasmonic nanostructures and consequent fluid convection recently attracted wide attention; however, the possibility of controlling and manipulating liquid surfaces has been sparsely investigated. The plasmon heating and convective fluid flow lead to the emergence of the surface tension gradient on a free liquid surface interface with air, resulting in the Marangoni effect‐driven fluid flow observed as water deformation. Here, nanoscale asymmetric fluid deformation anchored on the chiral plasmon‐induced optofluidic effect is reported on. To understand the fluid dynamics of surface deformation, a theoretical model is developed. The results demonstrate that deformation at different depths can be obtained by adjusting structural parameters or incident light intensity. The fundamental understanding of light‐induced asymmetric deformation will contribute to expanding chirality‐related discipline and open new avenues for controlling fluid flow at the micro‐ or nano‐scale. The proposed method can encourage the research and applications of optofluidics, including integrated fluidic devices, biochemistry, and clinical biology. Moreover, the use of the asymmetric fluid deformation on thermal dewetting of thin films of polymer solutions can be employed for the fabrication of functional and nanopatterned metal/polymer metasurfaces.

Chiro-plasmon responses of x-shaped titanium nitride (TiN) nanoarrays by numerical simulations

“…By combining chiral metamaterials with plasmonic materials, their chiral optical responses, such as circular dichroism (CD) are able to be tuned and regulated, which take advantage of both the unique plasmon properties and chiral metamaterials. Chiral plasmon metamaterials have found broad applications in various fields such as chiral sensing [2][3][4], optical devices [5,6], analytical chemistry [7][8][9], and so on [10][11][12][13][14]. As one of the crucial parameters of chiral optical response, CD is defined as the difference in the absorption of chiral structures illuminated by left-handed and right-handed circularly polarized lights [15], and it is also reported to be estimated by the spectra difference in the scattering, extinction and/or transmittance spectra [16][17][18].…”