Solution of cavity resonance and waveguide scattering problems using the eigenmode projection technique

Nasr, Mohamed; Othman, Mohamed A. K.; Eshrah, Islam A.; Abuelfadl, Tamer M.

doi:10.1063/1.4979860

Cited by 6 publications

(2 citation statements)

References 30 publications

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“…The structure is composed of a VO 2 layer sandwiched between a-Si and a continuous Ag bottom reflector. Due to the resonating nature of the structure [40][41][42], CST Microwave Studio Eigen-solver is utilized to have an initial guess regarding the dimension of the parameters of the structure and the resonance wavelengths in the NIR region which are useful for the future optimization. Accordingly, the bottom layer is chosen to be 100 nm, with no transmission in our desired range.…”

Section: Structure and Simulation Setupmentioning

confidence: 99%

Active Tuning from Narrowband to Broadband Absorbers Using a Sub-wavelength VO2 Embedded Layer

et al. 2021

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Metamaterial perfect absorbers (MPAs) with dynamic thermal tuning features are able to control the absorption performance of the resonances, providing diverse applications spanning from optical switches and filters to modulators. In this paper, we propose an MPA with diverse functionalities enabled by vanadium dioxide (VO 2 ) embedded in a metal-dielectric plasmonic structure. For the initial design purpose, a silicon (Si) nanograting on a silver (Ag) mirror is proposed to have multiple resonant responses in the near infrared (NIR) region. Then, the insertion of a thin VO 2 layer at the right position enables the design to act as an on/off switch and resonance tuner. In the insulator phase of VO 2 , in which the permittivity data of VO 2 is similar to that of Si, a double strong resonant behavior is achieved within the NIR region. By increasing the temperature, the state of VO 2 transforms from insulator to metallic so that the absorption bands turn into three distinct resonant peaks with close spectral positions. Upon this transformation, a new resonance emerges and the existing resonance features experience blue/ red shifts in the spectral domain. The superposition of these peaks makes the overall absorption bandwidth broad. Although Si has a small thermo-optic coefficient, owing to strong light confinement in the ultrasmall gaps, a substantial tuning can be achieved within the Si nanogratings. Therefore, the proposed hybrid design can provide multi-resonance tunable features to cover a broad range and can be a promising strategy for the design of linearly thermal-tunable and broadband MPAs. Owing to the proposed double tuning feature, the resonance wavelengths exhibits great sensitivity to temperature, covering a broad wavelength range. Overall, the proposed design strategy demonstrates diverse functionalities enabled by the integration of a thin VO 2 layer with plasmonic absorbers.

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Section: Structure and Simulation Setupmentioning

confidence: 99%

Active Tuning from Narrowband to Broadband Absorbers Using a Sub-wavelength VO2 Embedded Layer

et al. 2021

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“…An interesting consequence of the above geometrical configuration is the emergence of quasi-bound states associated to the one-sided leaking (C) rectangular structure placed at the closed end of the semi-infinite waveguide. Actually, there are different procedures [44,45] to generate resonances in cavities and closed waveguides [18]. For instance, one goal is try to enhance the intensity of the resulting stationary electromagnetic modes [44].…”

Section: Applications For the Domain V As The Rectangular Semi-infini...mentioning

confidence: 99%

The flexibility in choosing distinct Green’s functions for the boundary wall method: waveguides and billiards

Teston¹,

Azevedo²,

Sales³

et al. 2022

J. Phys. A: Math. Theor.

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The boundary wall method (BWM) is a general purpose procedure to treat boundary value problems for wave equations, specially Helmholtz’s (the case addressed here). Similarly to most protocols for boundary value problems, the BWM may be computationally demanding for large borders C, at which the wave function must satisfies determined boundary conditions. Also, although an exact approach, it is rarely amenable to closed solutions. The BWM employs the Green’s function G 0 of the embedding domain V of C. However, in many instances — like for C modeling a billiard — the specific V is not really fundamental and thus one has a certain freedom to choose distinct domains and so G 0 ’s. Here we consider this characteristic of the BWM and show how to obtain some analytical results and solve numerically semi- infinite waveguides by exploring proper Green’s functions. Explicit calculations for Dirichlet and leaking boundaries for rectangular, triangular and trapezoidal structures are presented as well as scattering states within semi-infinite rectangular waveguides.

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Wave amplitude gain within wedge waveguides through scattering by simple obstacles

Azevedo,

Maioli,

Teston

et al. 2024

Phys. Rev. E

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Solution of cavity resonance and waveguide scattering problems using the eigenmode projection technique

Cited by 6 publications

References 30 publications

Active Tuning from Narrowband to Broadband Absorbers Using a Sub-wavelength VO2 Embedded Layer

Active Tuning from Narrowband to Broadband Absorbers Using a Sub-wavelength VO2 Embedded Layer

The flexibility in choosing distinct Green’s functions for the boundary wall method: waveguides and billiards

Wave amplitude gain within wedge waveguides through scattering by simple obstacles

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