Switching on Versatility: Recent Advances in Switchable Plasmonic Nanostructures

Abstract

Plasmonic nanostructures are emerging as a promising avenue for nanophotonics due to their extreme light and thermal confinement, ultrafast manipulation processes, and potential uses in device miniaturization. However, their fixed functions have limited their versatility in applications. This review provides an overview of recent switchable plasmonic nanostructure engineering techniques, focusing on methods that provide reversible switchability. Passive optical switching, active structure‐tunable switching, active material‐based switching, and advanced applications, such as multifunctional biomedical sensing, energy harvesting, and dynamic optical devices, are discussed. The specific methods and techniques used to engineer switchable plasmonic nanostructures are also highlighted. By understanding the latest developments and overall trends, this review is expected to help researchers design and fabricate advanced plasmonic nanostructures with unprecedented switchability and versatility for various applications.

Deep Neural Operator Enabled Concurrent Multitask Design for Multifunctional Metamaterials Under Heterogeneous Fields

“…The proposed design framework is supposed to navigate the vast design space, jointly formed by M‐A‐S entities, with a possibly conflicting target tasks addressed along the way. More specifically, we are interested in A‐S concurrent optimization for metasurfaces that are programmable under spatial phase modulation, [ 58,59,73–75 ] which offer a means to embody multifunctionality with a geometrically stationary metasurface. In addition, the presented framework is applicable for more than two target functional states, as opposed to a plethora of demonstrations done for on‐off type programmability, [ 87–93 ] mostly presented without the trade‐off investigated.…”

“…Active light control using metasurfaces paves a way to enhance the speed of nanoscale optical imaging using far‐field optical components. [ 100,101 ] Spatial phase modulation [ 58,59,73–75 ] offers a route to dynamically address light confinement on plasmonic metasurfaces. [ 102 ] The inverse problem involves two key designable entities: plasmonic meta‐atoms (Section 2.3), whose array channels propagating light into localized evanescent electromagnetic waves on the sample surface, and phase distributions in the incoming wave (Section 3.1), whose distribution can be modulated through commercial spatial light modulators.…”

“…To show the efficacy of the framework, design of spatially addressable plasmonic metasurfaces [ 58,59,73–75 ] is revisited as a case study, where the design goal is to embody a “metasurface chessboard” maneuverable with spatial light modulators (Section 3). As opposed to the prior reports that simplified the problem setting to make it amenable, we tackle all the core challenges simultaneously, namely a)drastically varying fields involving heterogeneously distributed plasmonic hotspots b)opaque long‐range interaction across meta‐atoms c)the vast input space jointly formed by both a quasi‐freeform metasurface supercell and spatially modulated phase field d)a trade‐off across the figure‐of‐merits (FoM) associated with the multiple target focusing patterns of interest. …”

Nanoscale fluctuation-enhanced axial localization microscopy integrated with metallic structure-assisted fluidic chips

“…Addressing the need for a more accessible and cost-effective solution, this study proposes nanoscale fluctuation-enhanced axial localization microscopy as a promising technique for improving axial resolution. This method introduces incorporation of metallic structures, specifically reflective optical devices, within the framework of dynamic speckle illumination microscopy (DSI) [16][17][18] , drawing upon insights gained from prior approaches that exploit metallic structures and adopt various structured illumination [19][20][21][22][23][24][25][26][27][28] . Experimental investigation with 100-nm fluorescent beads and the U-87 MG cell membrane demonstrates accessible axial-resolving performance of fluctuation-enhanced axial imaging.…”

Multi-wavelength and broadband plasmonic switching with V-shaped plasmonic nanostructures on a VO2 coated plasmonic substrate

“…Although numerous plasmonic switches based on PCMs have been proposed previously [60][61][62][63], there have been limited reports of plasmonic switches offering multiwavelength switching (i.e. simultaneous switching at multiple wavelengths) and broadband operation (i.e.…”