Phytochemical study of the aerial parts of INULA VISCOSA resulted in the isolation of sixteen flavonoids. One of them, 3- O-acetylpadmatin [(2 R,3 R)-3-acetoxy-5,3',4'-trihydroxy-7-methoxyflavanone], was isolated for the first time as a natural compound. Ferulic aldehyde, 2-methylphloroacetophenone, inuviscolide and 2-deacetoxyxanthinin were also isolated.

A one-dimensional dielectric grating, based on a simple geometry, is proposed and investigated to enhance light absorption in a monolayer graphene exploiting guided mode resonances. Numerical findings reveal that the optimized configuration is able to absorb up to 60% of the impinging light at normal incidence for both TE and TM polarizations resulting in a theoretical enhancement factor of about 26 with respect to the monolayer graphene absorption (≈2.3%). Experimental results confirm this behavior showing CVD graphene absorbance peaks up to about 40% over narrow bands of a few nanometers. The simple and flexible design points to a way to realize innovative, scalable and easy-to-fabricate graphene-based optical absorbers.

We investigate graphene-based optical absorbers that exploit guided mode resonances (GMRs) attaining theoretically perfect absorption over a bandwidth of few nanometers (over the visible and near-infrared ranges) with a 40-fold increase of the monolayer graphene absorption. We analyze the influence of the geometrical parameters on the absorption rate and the angular response for oblique incidence. Finally, we experimentally verify the theoretical predictions in a one-dimensional, dielectric grating by placing it near either a metallic or a dielectric mirror, thus achieving very good agreement between numerical predictions and experimental results.

Perfect, narrow-band absorption is achieved in an asymmetric 1D photonic crystal with a monolayer graphene defect. Thanks to the large third-order nonlinearity of graphene and field localization in the defect layer we demonstrate the possibility to achieve controllable, saturable absorption for the pump frequency.

In this paper, we report on the engineering and the realization of optically transparent graphene-based microwave devices using Chemical Vapour Deposition (CVD) graphene whose sheet resistance may be tailored down to values below 30 Ω/sq. In particular, we show that the process was successfully used to realize and characterize a simple, optically transparent graphene-based wire-grid polarizer at microwave frequencies (X band). The availability of graphene operating in a quasi-metallic region may allow the integration of graphene layers in several microwave components, thus leading to the realization of fully transparent (and flexible) microwave devices.

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We employ a classical, nonlinear Lorentz-Duffing oscillator model to predict third harmonic conversion efficiencies in the ultrafast regime, from a variety of metal nanostructures, including smooth, isolated metal layers, a metal-dielectric photonic band gap structure, and a metal grating. As expected, the plasmonic grating yields the largest narrow-band conversion efficiencies. However, interference phenomena at play within the multilayer stack yield comparable, broadband conversion. The method includes both linear and nonlinear material dispersions that in turn sensitively depend on linear oscillator parameters. Concurrently, and unlike other techniques, the integration scheme is numerically stable. By design, one thus avoids the introduction of explicit, third-order nonlinear coefficients and also takes into account linear and nonlinear material dispersions simultaneously, elements that are often necessary to fully understand many of the subtleties of the interaction of light with matter.

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