Plasmon dispersion diagram and localization effects in a three-cavity commensurate grating

Abstract

Commensurate gratings of deep-metallic grooves have highly localized cavity resonances which do not exist for purely periodic gratings. In this paper we present the experimental dispersion diagram of the resonances of a commensurate grating with three sub-wavelength cavities per period. We observe selective light localization within the cavities, transition from a localized to a delocalized mode and modifications of the coupling of modes with the external plane-wave that may lead to the generation of black modes. This unexpected complexity is analyzed via a theoretical study in full agreement with the experiments. These results open a way to the control of wavelength-dependent hot spot predicted in more complex commensurate gratings.

Millimeter-wave phase resonances in compound reflection gratings with subwavelength grooves

“…The quality of those other resonances is not as high as that of the π resonance, and the magnetic field within the grooves is not as strong as in the π-mode (not shown) [15]. The results reported here in the millimeter-wave regime are in qualitative agreement with previous measurements of phase resonances in the infrared region [19,25]. The π resonance (called symmetric and pseudosymmetric mode in [19] and [25], respectively) emerges both at normal incidence and at 5 deg and has the strongest field enhancement inside the grooves, as stated in [19] and [25].…”

“…3(b)], the π resonance at f ≈ 60 GHz is still present in the measured as well as in the simulated reflectance, and there is also another minimum at f ≈ 57 GHz, which corresponds to the excitation of another, non-symmetric phase resonance [31]. As observed, there is a good agreement between the experimental and the simulated results, and these results are in qualitative agreement with previously reported experimental data in the infrared region [19,25]. However, it is important to remark that in all cases the measured dips are wider than the simulated ones, as it is to expect due to a variety of reasons: small period changes along the fabricated structure, experimental Gaussian beam illumination, which is non-uniform, reception of power employing a horn antenna, instead of the point magnetic field probe used in the simulation.…”

“…For reflection gratings with dual-period, reflectance measurements have been reported in [24], where the authors analyze the excitation of surface plasmons and the absorption they produce at resonance. Recently, Barbara et al gave experimental evidence of phase resonance excitation in the infrared region [19,25].…”

Optimized Superconducting Nanowire Single Photon Detectors to Maximize Absorptance

“…Common advantage of NCTAI-A-SNSPDs is that they consist of in-plane gold segments, exclusively, and the optimal polar angles are further reduced compared to corresponding NCDDAI-A-SNSPDs. The NCTAI-A devices can be considered as the simplest compound gratings [70,71]. The effect of distributed gratings consisting of different periodic components as well as the possible advantages of tilted cavity and trench walls is a subject of further studies [63,65].…”

Wavelength-selective mid-infrared metamaterial absorbers with multiple tungsten cross resonators

“…, where 1 ε and 2 ε denotes the permittivity of metal and dielectric, respectively. It is noted that spoof surface plasmons are usually considered for 1D or 2D periodic metamaterials under TM polarization [44,46], however, spoof surface plasmons also exist under TE polarization for 2D case [45]. For a 2D periodic metamaterial absorber, to excite spoof surface plasmons, momentum matching condition (i.e.…”