Two-dimensional metallic broadband absorbers on a SiO₂/Ag/Si substrate were experimentally studied. The absorptivity of such structure can be increased by tailoring the ratio of disk size to the unit cell area. The metallic disk exhibits a localized surface plasmon polariton (LSPP) mode for both TE and TM polarizations. A broadband thermal emitter can be realized because the LSPP mode is independent of the periodicities. By manipulating the ratios and disk sizes, a high-performance, wide-angle, polarization-independent dual band absorber was experimentally achieved. The results demonstrated a substantial flexibility in absorber designs for applications in thermal photovoltaics, sensors, and camouflage.

All-optical devices based on surface plasmon polaritons (SPPs) have been the topic of comprehensive research in recent years. All-optical SPP devices have extensively motivated new actions to overcome the major performance constraints of semiconductor electronic devices, which suffer from ingrained delay and high-heat generation, and to overcome the problem of photonics devices, that is, the diffraction limit. Therefore, the utilization of the aforementioned devices enabled the manipulation of light on a subwavelength scale.¹ SPPs are the interaction of electromagnetic waves and the free electrons of metals, propagating on the metal–dielectric or dielectric–metal interfaces.^2,3 Different passive and active plasmonic devices, such as nanocavities,⁴ Bragg reflectors,⁴ splitters,⁵ resonators,⁶ couplers,⁷ modulators,⁸ multi/demultiplexers,⁹ stub waveguides,⁵ hybrid plasmonic waveguides,¹⁰ switches,^11,12 and logic gates,¹³ 14. 15. 16. 17. ^{– 18} have been realized so far. On the subject of all-optical logic gates, several studies have been proposed, analyzed, and investigated, for example, single semiconductor optical amplifiers,¹⁹ hybrid plasmonic-photonic crystal nanobeam cavities,¹⁸ two-photon absorption in silicon waveguides,²⁰ silicon microring resonators,^21,22 cross-phase modulation,²³ and nanophotonic plasmonics.²⁴

A T-shaped plasmonic array is proposed for application as an effective thermal emitter or biosensor. The reflection and thermal radiation properties of a T-shaped array are investigated theoretically. The angular dependent reflectance spectrum shows a clear resonant dip at 0.36eV for full polar angles. No other significant localized resonant mode is found in the investigated spectral range from 0.12eV to 0.64eV. According to the Kirchhoff’s law, the thermal radiation of the proposed structure can lead to a sharp peak at 3.5µm with low sideband emission. We have also found that the T-shaped structure filled with organic material such as PMMA with different thicknesses (10 nm -50 nm) can lead to significant shift of the resonance wavelength. Thus, the T-shaped structure can also be used as a good sensor for organic materials.

It is shown that the metallic disk structure can be used as an efficient narrow-band thermal emitter in the IR region. The absorption spectra of such structure are investigated both theoretically and experimentally. Calculations of thermal radiation properties of the metallic disk show that the metallic disk is a perfect emitter at a specific wavelength, which can be tuned by varying the diameter of the disk. The metallic disk exhibits only one significant localized surface plasmon polariton (LSPP) mode for both TM and TE polarizations simultaneously. The LSPP mode can be tuned by either varying the disk diameter or the spacer (made of ${\text{SiO}}_2$ ).

In this paper, we propose, analyze and simulate a new configuration to simulate all-optical combinational logic functions based on Nano-rings insulator-metal-insulator (IMI) plasmonic waveguides. We used Finite Element Method (FEM) to analyze the proposed plasmonic combinational logic functions. The analyzed combinational logic functions are Half-Adder, Full-Adder, Half-Subtractor, and Comparator One-Bit. The operation principle of these combinational logic functions is based on the constructive and destructive interferences between the input signal(s) and control signal. Numerical simulations show that a transmission threshold exists (0.25) which allows all proposed four plasmonic combinational logic functions to be achieved in one structure. As a result, the transmission threshold value measures the performance of the proposed plasmonic combinational logic functions. We use the same structure with the same dimensions at 1550 nm wavelength for all proposed plasmonic combinational logic functions. The proposed all-optical combinational logic functions structure contributes significantly to photonic integrated circuits construction and all-optical signal processing nano-circuits.

<!-- *** Custom HTML *** --> We propose, simulate, and achieve a method of realization of all-optical reversible logic gates based on nanoring dielectric-metal-dielectric plasmonic waveguides at 1550 nm and in the same structure. Finite-element method was used to study and simulate the proposed plasmonic reversible logic gates. These reversible logic gates are wire, NOT, swap, and Feynman. The working principle of the proposed reversible gates is based on the interferences (destructive or constructive) between the light that propagates in the input signal port(s) and control signal port(s). The threshold value of transmission between OFF and ON states is proposed as 0.4. Finally, the designed area of the proposed structure is very small (300 nm × 460 nm). These plasmonic reversible gates can contribute in construction of nanophotonic reversible logic circuits and all-optical quantum computing.