All-dielectric metasurfaces comprising arrays of nanostructured high-refractive-index materials are re-imagining what is achievable in terms of the manipulation of light. However, the functionality of conventional dielectric-based metasurfaces is fixed by design; thus, their optical response is locked in at the fabrication stage. A far wider range of applications could be addressed if dynamic and reconfigurable control were possible. We demonstrate this here via the novel concept of hybrid metasurfaces, in which reconfigurability is achieved by embedding sub-wavelength inclusions of chalcogenide phase-change materials within the body of silicon nanoresonators. By strategic placement of an ultra-thin G e 2 S b 2 T e 5 layer and reversible switching of its phase-state, we show individual, multilevel, and dynamic control of metasurface resonances. We showcase our concept via the design, fabrication, and characterization of metadevices capable of dynamically filtering and modulating light in the near infrared (O and C telecom bands), with modulation depths as high as 70% and multilevel tunability. Finally, we show numerically how the same approach can be re-scaled to shorter wavelengths via appropriate material selection, paving the way to additional applications, such as high-efficiency vivid structural color generators in the visible spectrum. We believe that the concept of hybrid all-dielectric/phase-change metasurfaces presented in this work could pave the way for a wide range of design possibilities in terms of multilevel, reconfigurable, and high-efficiency light manipulation.

Metasurfaces and nanoantennas are redefining what can be achieved in terms of optical beam manipulation, as they provide a versatile design platform towards moulding the flow of light at will. Yet, once a conventional metasurface is designed and realised, its effect on optical beams is repeatable and stationary, thus its performance is 'locked-in' at the fabrication stage. A much wider range of applications, such as dynamic beam steering, reconfigurable and dynamic lensing, optical modulation and reconfigurable spectral filtering, could be achieved if real-time tuning of metasurface optical properties were possible. Chalcogenide phase-change materials, because of their rather unique ability to undergo abrupt, repeatable and non-volatile changes in optical properties when switched between their amorphous and crystalline phases, have in recent years been combined with metasurface architectures to provide a promising platform for the achievement of dynamic tunability. In this paper, the concept of dynamically tunable phase-change metasurfaces is introduced, and recent results spanning the electromagnetic spectrum from the visible right through to the THz regime are presented and discussed. The progress, potential applications, and possible future perspectives of phase-change metasurface technology are highlighted, and requirements for the successful implementation of real-world applications are discussed.

The true integration of electronics into textiles requires the fabrication of devices directly on the fibre itself using high-performance materials that allow seamless incorporation into fabrics. Woven electronics and opto-electronics, attained by intertwined fibres with complementary functions are the emerging and most ambitious technological and scientific frontier. Here we demonstrate graphene-enabled functional devices directly fabricated on textile fibres and attained by weaving graphene electronic fibres in a fabric. Capacitive touch-sensors and light-emitting devices were produced using a roll-to-roll-compatible patterning technique, opening new avenues for woven textile electronics. Finally, the demonstration of fabric-enabled pixels for displays and position sensitive functions is a gateway for novel electronic skin, wearable electronic and smart textile applications.

In recent years, silicon nitride has drawn attention for the realisation of integrated photonic devices due to its fabrication flexibility and advantageous intrinsic properties that can be tailored to fulfill the requirements of different linear and non-linear photonic applications. This paper focuses on our progress in the demonstration of enhanced functionalities in the near infrared wavelength regime with our low temperature (<350 • C) SiN platform. It discusses (de)multiplexing devices, nonlinear all optical conversion, photonic crystal structures, the integration with novel phase change materials, and introduces applications in the 2 µm wavelength range.