An electromechanically reconfigurable metamaterial operating in the near infrared Nature Nanotechnology (2013)

The first metamaterial electro-optic modulator for the telecommunications band

Current efforts in metamaterials research focus on attaining dynamic functionalities such as tunability, switching and modulation of electromagnetic waves1. To this end, various approaches have emerged, including embedded varactors2, phase-change media3, 4, the use of liquid crystals5, 6, electrical modulation with graphene7, 8 and superconductors9, and carrier injection or depletion in semiconductor substrates10, 11. However, tuning, switching and modulating metamaterial properties in the visible and near-infrared range remain major technological challenges: indeed, the existing microelectromechanical solutions used for the sub-terahertz12and terahertz13, 14, 15 regimes cannot be shrunk by two to three orders of magnitude to enter the optical spectral range. Here, we develop a new type of metamaterial operating in the optical part of the spectrum that is three orders of magnitude faster than previously reported electrically reconfigurable metamaterials. The metamaterial is actuated by electrostatic forces arising from the application of only a few volts to its nanoscale building blocks—the plasmonic metamolecules—that are supported by pairs of parallel strings cut from a flexible silicon nitride membrane of nanoscale thickness. These strings, of picogram mass, can be driven synchronously to megahertz frequencies to electromechanically reconfigure the metamolecules and dramatically change the transmission and reflection spectra of the metamaterial. The metamaterial’s colossal electro-optical response (on the order of 10−5–10−6 m V−1) allows for either fast continuous tuning of its optical properties (up to 8% optical signal modulation at up to megahertz rates) or high-contrast irreversible switching in a device only 100 nm thick, without the need for external polarizers and analysers.

Ref:

An electromechanically reconfigurable plasmonic metamaterial operating in the near-infrared
J. Y. Ou, E. Plum, J. Zhang, and N. I. Zheludev
Nature Nanotech. 8, 252-255 (2013) doi: 10.1038/NNANO.2013.25

Press coverages

Exotic optics: Metamaterial world
Nature: News Feature, Aug 2013 – link

Electrical signals dictate optical properties
Nanotechnology Now, Mar 2013 – link

Electrical Signals Dictate Optical Properties
Science Daily, Mar 2013 – link

Electrical signals dictate optical properties of metamaterial
Laser Focus World, Mar 2013 – link

Metamaterial with adjustable optical properties
R&D, Mar 2013 – link

Variable-property metamaterial has optical application potential
the ENGINEER, Mar 2013 – link

 

Optomechanical metamaterials with giant nonlinearity Advanced Materials (2016) 

The first demonstration of light driven optomechanical metamaterials exhibiting giant nonlinearity in the near infrared.

Metamaterial nanostructures actuated by light give rise to a large optical nonlinearity. Plasmonic metamolecules on a flexible support structure cut from a dielectric membrane of nanoscale thickness are rearranged by optical illumination. This changes the optical properties of the strongly coupled plasmonic structure and therefore results in modulation of light with light.

Ref:
Giant nonlinearity of an optically reconfigurable plasmonic metamaterial
J. Y. Ou, E. Plum, J. Zhang, and N. I. Zheludev
Adv. Mater. 28, 729-733 (2016) doi: 10.1002/adma.201504467

Reconfigurable Photonic Metamaterials   Nano Letters (2011) 

The first demonstration of thermal actuated reconfigurable metamaterial in the near-infrared.
We introduce mechanically reconfigurable photonic metamaterials (RPMs) as a flexible platform for realizing metamaterial devices with reversible and large-range tunable characteristics in the optical part of the spectrum. Here we illustrate this concept for a temperature-driven RPM exhibiting reversible relative transmission changes of up to 50%.

Ref:
Reconfigurable photonic metamaterials
J. Y. Ou, E. Plum, L. Jiang, and N. I. Zheludev
Nano Lett. 11(5), 2142-2144 (2011) doi: 10.1021/nl200791r

Visible range plasmonics in the topological insulator Nature Communications (2014) 

The development of metamaterials, data processing circuits and sensors for the visible and ultraviolet parts of the spectrum is hampered by the lack of low-loss media supporting plasmonic excitations. This has driven the intense search for plasmonic materials beyond noble metals. Here we show that the semiconductor Bi1.5Sb0.5Te1.8Se1.2, also known as a topological insulator, is also a good plasmonic material in the blue-ultraviolet range, in addition to the already-investigated terahertz frequency range. Metamaterials fabricated from Bi1.5Sb0.5Te1.8Se1.2 show plasmonic resonances from 350 to 550 nm, while surface gratings exhibit cathodoluminescent peaks from 230 to 1,050 nm. The observed plasmonic response is attributed to the combination of bulk charge carriers from interband transitions and surface charge carriers of the topological insulator. The importance of our result is in the identification of new mechanisms of negative permittivity in semiconductors where visible range plasmonics can be directly integrated with electronics.

Ref:
Ultraviolet and visible range plasmonics in the topological insulator Bi1.5Sb0.5Te1.8Se1.2
J. Y. Ou, J. K. So, G. Adamo, A. Sulaev, L. Wang, and N. I. Zheludev
Nat. Commun., 5, 5139 (2014) doi: 10.1038/ncomms6139