No abstract

CommuniCation(1 of 6) 1600829 and immune to bleach, thus hold great potentials in display, [6,7] anticounterfeiting technology, [19] etc.Structural colors are typically produced by diffractive gratings (with or without guided mode resonance (GMR)), [20][21][22] Fabry-Pérot cavity, [18] photonic crystals (PCs), [23,24] plasmonics, [1,[25][26][27] etc. Dynamic color tuning is a very important and fascinating direction in the field of structural colorations, because of its possible applications in stealthy, anticounterfeiting and displaying techniques. The resonant wavelengths of filters based on GMR effect are very sharp, resulting in high purity and brightness colors. Dynamic tuning of the GMR can be achieved by adopting the index-tunable materials as the waveguide layers. However, the possible color tuning gamut might be limited without the large index changes. Alternatively, the interferometric modulator display, a type of Fabry-Pérot cavity, can achieve the dynamic tunability of spectra via gap changing of the cavity controlled by the microelectromechanical system. This can produce a continuously varying color in the whole visible range, [18] but the strategy requires a complex controlling system, which is unfavorable for optoelectronic integration. The PCs can also provide dynamically tunable capability of the resonant wavelengths with the change of refractive indices of dielectrics in PC structures. [23,24] Plasmonics is known to offer a platform for transformative applications in optical frequency. [28][29][30][31] Nevertheless, plasmon in conventional nanoscale metallic systems cannot easily support the dynamical tunability because of the rigid structures or devices, except when it is composed of some certain materials or compound structures with tunable properties, such as optoelectronic or electrochemical materials, graphene, etc. [32][33][34][35][36] Herein, we propose and demonstrate a method to create actively tunable structural color based on tensile substrate, [37][38][39][40] i.e., polydimethylsiloxane (PDMS). PDMS, one of the most widely used silicon-based organic polymer, is particularly known for its unusual properties, [41] such as inert, nontoxic, and nonflammable. Taking advantage of the viscoelastic [42] and chemical stable [43] properties, elastic deformations (e.g., tension) of PDMS can be easily occurred under the external force. Therefore, the period of the structure on PDMS will change simultaneously, which causes the dynamic tuning of the surface plasmon resonance (SPR) wavelength, as the phase-matching condition changes. Moreover, compared to the previous dielectric-PDMS composed

A novel graphene photodetector with graphene embedded in a metamaterial perfect absorber (MPA) is proposed and its light absorption property is numerically investigated. Absorption above 40% in graphene is obtained, which is over 17 times that of a bare monolayer graphene. Both horizontally and vertically cascaded MPAs integrated with graphene are also investigated.