Designed ultrafast optical nonlinearity in a plasmonic nanorod metamaterial enhanced by nonlocality

Abstract

All-optical signal processing enables modulation and transmission speeds not achievable using electronics alone. However, its practical applications are limited by the inherently weak nonlinear effects that govern photon-photon interactions in conventional materials, particularly at high switching rates. Here, we show that the recently discovered nonlocal optical behaviour of plasmonic nanorod metamaterials enables an enhanced, ultrafast, nonlinear optical response. We observe a large (80%) change of transmission through a subwavelength thick slab of metamaterial subjected to a low control light fluence of 7 mJ cm(-2), with switching frequencies in the terahertz range. We show that both the response time and the nonlinearity can be engineered by appropriate design of the metamaterial nanostructure. The use of nonlocality to enhance the nonlinear optical response of metamaterials, demonstrated here in plasmonic nanorod composites, could lead to ultrafast, low-power all-optical information processing in subwavelength-scale devices.

Nanoscale Artificial Plasmonic Lattice in Self‐Assembled Vertically Aligned Nitride–Metal Hybrid Metamaterials

“…Some extraordinary optical properties in the visible range have been investigated for these hyperbolic metamaterials,15, 24, 25 such as the silver (Ag)15 and gold (Au)24, 25 nanowires in porous alumina template. The limitations lie in the costly template, the complicated and tedious nanofabrication methods, and the challenges for large‐scale processing with nanoscale features.…”

Ferrell–Berreman Modes in Plasmonic Epsilon-near-Zero Media

“…This enhanced absorption in ENZ media has been exploited for novel polarization control and filtering in thin films [6], as well the proposal to use ENZ absorption resonances to tune thermal blackbody radiation of a heated object to the band-gap of a photovoltaic cell [7]. An enhanced non-linear response based upon strong spatial dispersion of waves in ENZ media has been demonstrated, and proposed for all-optical switching [8,9].Here we show theoretically and experimentally that ENZ metamaterials support unique absorption resonances related to radiative bulk plasmon-polaritons of thin metal films. These radiative bright modes exhibit properties in stark contrast to conventional dark modes of thin-film media (surface plasmon polaritons).…”

Hotspot-mediated ultrafast nonlinear control of multifrequency plasmonic nanoantennas

“…Subwavelength focusing of energy is of enormous interest for many applications including coupling of light to single molecules [3,4], field-enhanced spectroscopy and sensing [5][6][7][8][9], photochemistry [10], nonlinear frequency conversion [11,12], and all-optical switching [13][14][15][16]. In analogy with radiowave antennas, plasmonic nanoantennas are designed to optimize the coupling between far-field light and near-field 'hotspots' [5,[17][18][19].…”

“…In order to successfully achieve effective optical control at the single nanoantenna level, new types of nanoscale hybrid nonlinearities have to be devised [11,[14][15][16]. One of the largest optical nonlinearities in nanoplasmonics is generated by the metal itself, through a combination of interband excitations [13,20], hot-plasma effects [16,[21][22][23] and electronic charging [24]. While these nonlinearities of the plasmonic metal can be employed for modulation devices, they are generally associated with a considerable thermal loading of the device and are accompanied by slow thermal relaxation effects.…”