Colour generation by plasmonic nanostructures and metasurfaces has several advantages over dye technology: reduced pixel area, sub-wavelength resolution and the production of bright and non-fading colours. However, plasmonic colour patterns need to be pre-designed and printed either by e-beam lithography (EBL) or focused ion beam (FIB), both expensive and not scalable processes that are not suitable for post-processing customization. Here we show a method of colour printing on nanoimprinted plasmonic metasurfaces using laser post-writing. Laser pulses induce transient local heat generation that leads to melting and reshaping of the imprinted nanostructures. Depending on the laser pulse energy density, different surface morphologies that support different plasmonic resonances leading to different colour appearances can be created. Using this technique we can print all primary colours with a speed of 1 ns per pixel, resolution up to 127,000 dots per inch (DPI) and power consumption down to 0.3 nJ per pixel.

Colors of materials are precisely laser-controlled using new manufacturing technology with nanopatterned semiconductor surfaces.

The combination of graphene with noble-metal nanostructures is currently being explored for strong light-graphene interaction enhanced by plasmons. We introduce a novel hybrid graphene-metal system for studying light-matter interactions with gold-void nanostructures exhibiting resonances in the visible range. Strong coupling of graphene layers to the plasmon * To whom correspondence should be addressed † DTU Fotonik ‡ CNG ¶ Fudan University § DTU Nanotech CINF 1 modes of the nanovoid arrays results in significant frequency shifts of the underlying plasmon resonances, enabling more than 30% absolute light absorption in a single layer of graphene and up to 700-fold enhancement of the Raman response of the graphene. These new perspectives enable us to verify the presence of graphene on gold-void arrays and the enhancement even allows us to accurately quantify the number of layers. Experimental observations are further supported by numerical simulations and perturbation-theory analysis. The graphene gold-void platform is beneficial for sensing of molecules and placing R6G dye molecules on top of the graphene, we observe a strong enhancement of the R6G Raman fingerprints. These results pave the way toward advanced substrates for surface-enhanced Raman scattering (SERS) with potential for unambiguous single-molecule detection on the atomically well-defined layer of graphene.Graphene is an atomic monolayer formed by carbon hexagons, whose extraordinary electrical and optical properties have led to a range of promising optoelectronic devices, 1-3 such as photodetectors, 4 optical modulators, 5 and ultra-fast lasers. 6 However, all such devices suffer from the inherently weak interaction between pristine graphene and light (2.3% light absorption at normal incidence), therefore imposing substantial challenges and restrictions for many electro-optical and all-optical applications. 7,8 Doped graphene nanostructures which support surface plasmons in the teraherz and infrared regions offer an exciting route to increase the light-graphene interaction by confining the optical fields below the diffraction limit. 9-13 However, graphene is less attractive when the interband loss becomes large, and it effectively mimics a dielectric material in the visible and near-infrared frequencies. 14 One alternative way to enhance the light-graphene interaction in short wavelengths is the combination of graphene with conventional plasmonic nanostructures based on noble metals. 15 These graphene-plasmonic hybrid structures could be beneficial for both fields of investigation: first of all, graphene can influence the optical response of plasmonic structures leading to graphene-based tunable plasmonics, 16 and in turn, plasmonic nanostructures can dramatically enhance the local electric field, leading to strong light absorption and Raman signature of graphene layers.In this Letter, a novel platform based on graphene-covered gold nanovoid arrays (GNVAs) is 2 proposed to enhance the light-matter interaction in graphene-plasmonic hybrid str...

Graphene-based photodetectors, taking the advantages of high carrier mobility and broadband absorption in graphene, have recently experienced rapid development. However, their performance with respect to responsivity and bandwidth is still limited by weak light-graphene interaction and large resistance-capacitance product. Here, we demonstrate a waveguide coupled integrated graphene plasmonic photodetector on a silicon-on-insulator platform. Benefiting from plasmonic enhanced graphene-light interaction and subwavelength confinement of the optical energy, we achieve a small-footprint grapheneplasmonic photodetector working at the telecommunication window, with large bandwidth beyond 110 GHz and high intrinsic responsivity of 360 mA/W. Attributed to the unique electronic bandstructure of graphene and its ultra-broadband absorption, operational wavelength range extending beyond mid-infrared, and possibly further, can be anticipated. Our results show that the combination of graphene with plasmonic devices has great potential to realize ultra-compact and high-speed optoelectronic devices for graphene-based optical interconnects. arXiv:1808.04815v3 [physics.app-ph]

With unique possibilities for controlling light in nanoscale devices, graphene plasmonics has opened new perspectives to the nanophotonics community with potential applications in metamaterials, modulators, photodetectors, and sensors. In this paper, we briefly review the recent exciting progress in graphene plasmonics. We begin with a general description of the optical properties of graphene, particularly focusing on the dispersion of graphene-plasmon polaritons. The dispersion relation of graphene-plasmon polaritons of spatially extended graphene is expressed in terms of the local response limit with an intraband contribution. With this theoretical foundation of graphene-plasmon polaritons, we then discuss recent exciting progress, paying specific attention to the following topics: excitation of graphene plasmon polaritons, electron-phonon interactions in graphene on polar substrates, and tunable graphene plasmonics with applications in modulators and sensors. Finally, we address some of the apparent challenges and promising perspectives of graphene plasmonics.