Resonant coupling to a dipole absorber inside a metamaterial: Anticrossing of the negative index response
(Color online) Side view schematic of the metal-dielectric-metal fishnet structure.
(Color online) (a) Simple physical model calculations for the effective permeability of the fishnet structure without the dielectric absorber; MSR is at (0. 136 eV) (top left). (b) RCWA calculated transmission with a dielectric material without an absorber; MSR is at (0.135 eV) (top right). A single MSR is observed for both models; (c) simple physical model calculations for the effective permeability with the dipole absorber (low left), where MSR is at (0.136 eV) and absorption resonance is at (0.130 eV); (d) RCWA calculated transmission (low right) of the fishnet structure with the presence of the dipole absorber in the dielectric; MSR is at (0.135 eV) and absorption resonance (abs) is at (0.130 eV). The hybridization of the resonances is clearly visible for both models.
(Color online) Anticrossing behavior of the structural and absorption resonances as the electric dipole resonance tuned through the bare fishnet resonance is clearly observed. A bare fishnet resonance at (0.135 eV) and an absorber resonance at (0.130 eV) are assumed. Good qualitative agreement between detailed RCWA calculation (red, short lines) and simple physical model (black, long lines) is obtained.
(Color online) Measured and data profiles for the BCB dielectric material used in the designed fishnet structure. There are absorption peaks at (0.155 eV) and at (0.130 eV) in the wavelength range of interest (area between the vertical dashed lines).
(Color online) Optical microscope images of the two extreme fishnet samples. Geometrical parameters for the critical dimensions are indicated on the images.
(Color online) Overlapped experimental (FTIR) and modeled (RCWA) transmission curves (left) and RCWA model for the corresponding effective refractive index (right) curve for the sample with MSR at (0.162 eV). Hybridized resonances , , and are indicated.
(Color online) FTIR experimental and RCWA modeled overlapped transmission curves for the samples with MSRs at (0.126 eV) on the left and (0.12 eV) on the right. Hybridized resonances and are indicated on both graphs.
(Color online) RCWA modeled sharing of the oscillator strength in the effective refractive index as the bare fishnet MSR is tuned though the absorber resonances. Calculated refractive index responses are from the samples with (1) MSR at (0.162 eV), solid, black curve; (5) MSR at (0.126 eV), dash double dot, red curve; and (7) MSR at (0.12 eV), dash dot, blue curve.. Resonances and share oscillator strength.
(Color online) Numerical RCWA model (blue, with triangular symbols) and experimental data (red, with hex symbols) demonstrate the classical anticrossing behavior of the fishnet structure with a BCB absorber with two dipole resonances at (0.157 eV) and (0.13 eV) in the dielectric material. Resonant frequencies of the fishnet structure are tuned through the electric dipole resonances of the bare absorber. Hybridization and an anticrossing behavior are clearly visible in both experimental and model data with good agreement.
Geometrical parameters of a fishnet structure with a structural resonance wavelength of .
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