Electro-plasmonic nanoantenna: A nonfluorescent optical probe for ultrasensitive label-free detection of electrophysiological signals

Abstract

An ultra-bright extracellular optical field probe enabling label-free detection of electrogenic activity is introduced.

Active plasmonic nanoantenna: an emerging toolbox from photonics to neuroscience

“…Based on Alù and Engheta's groundbreaking work [137], significant progress has been made by many other research groups [10,[140][141][142][143][144][145][146][147][148][149][150][151] in demonstrating novel uses of plasmonic devices with functionalities merging electronic/electrochemical/mechanical phenomena with optics at the nanoscale. Based on lumped optical nanocircuit theory, researchers demonstrated design, optimization, and analysis of novel practical PNA-based devices and realized plasmonic nano-optic devices that work seamlessly in the optical domain [10,139,147]. One of the most notable examples is the impedance-matched optical dimer nanoantennas designed using fully three-dimensional (3D) lumped nanocircuit models [147] ( Figure 5C).…”

“…A concerted and interdisciplinary effort has been devoted to the development of active systems in realization of postfabrication dynamic reconfigurability in a fully reversible and repeatable, fast, and ideally programmable manner. Until now, a variety of schemes have been proposed and developed in pursuit of in situ active control by electrical [153][154][155], chemical [156][157][158][159], optical [160], thermal [161], or mechanical [162][163][164] [165], tunable flat lenses [166], holograms [167], dynamic switches [66], interferometry photonic platforms [168], neural activity tracking [10,69], and information encryption [169]. Physical mechanisms behind these active plasmonic devices can be understood using lumped optical nanocircuit theory.…”

“…By exploiting coherent excitations of conduction electrons at metallic surfaces, they bridge the gap between the diffraction limited optics and nanoscale phenomena [2][3][4][5][6][7][8]. By creating local hotspots of the electric field at the nanometer scale, plasmonic nanostructures enhance lightmatter interactions by several orders of magnitude [9], paving the way to reinvention of the most known optical phenomena with previously unthinkable ways [10]. During the last couple of decades, we have witnessed transformative breakthroughs in a myriad of different research areas ranging from next-generation photovoltaic devices [11][12][13][14][15] and subdiffraction-limited imaging [13,[16][17][18] to ultrasensitive biosensing [13,16,[19][20][21][22][23][24] and photodynamic cancer therapy [13,16].…”

“…This presents a major hurdle for many practical applications that require a dynamic optical response. Active control over individual nanoantenna characteristics is inevitably needed for the advancement of future plasmonic technologies such as optical modulators [61][62][63][64], switches [65][66][67][68], and field-effect neurophotonic devices [10,69]. Dynamically reconfigurable plasmonics, commonly referred as "active plasmonics" [70,71], has attracted remarkable interest since the term coined in 2004 [72].…”

“…As evident by the rapidly increasing number of annual citations to active plasmonics-related scientific articles (Figure 1), this new research field continues to grow at an outstanding pace. Progress in this field has already facilitated development of novel active plasmonic devices with unprecedented photon management capabilities, leading to new physical phenomena and a broad range of new exciting practical applications [10,73,74]. Beyond their passive counterparts, active PNA technologies have shown remarkable characteristics, enabling researchers to achieve new device functionalities, including ultraprecise gas sensing [73] and wireless electrophysiological recordings at the diffraction limit of light [10].…”