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We propose a design approach for color absorbers based on a tri-layer metal-dielectric-metal (MDM) planar geometry, which maintains the same color absorbed, over a range of incident angles from 0° to 80° for light with TM polarization. The dielectrics are chosen to satisfy the ideal conditions of resonance. We calculate the ideal thickness of each dielectric layer by using the planar resonance theory. The numerical results show a total absorption above 85% for all colors of the absorber. We analyzed the influence of the of the metallic top layer thickness and we demonstrated the fabrication error tolerance of the proposed absorber. Finally, we present and discuss the physical mechanisms for the coupling of the electromagnetic field and the absorbed optical power in the structure.

We present a design for a highly efficient and omnidirectional color-selective filter for the visible spectrum, based on a Fabry-Perot metal-dielectric-metal nanoresonator. The filter can have the same color transmitted in a range of incident angles from 0° up to 60° for TM polarization. The dielectrics used for each color filter are carefully chosen so that the angle-insensitive resonance conditions are satisfied while transmission values from 44.3% to 78.36% are achieved. We calculated the dielectric thickness for each filter and analyzed the optimal Ag thickness for maximum transmission. The proposed filters have a simple multilayer structure and do not require complex lithographic fabrication processes.

A hybrid resonant absorber Fabry Perot—FP tunable from a simple stack of planar layers of ultra‐thin films of phase change material is proposed, designed, and demonstrated numerically. This work shows that properly designed metal–dielectric–metal) structures comprising thin films of titanium (Ti), germanium telluride (GeTe) on a silver (Ag) substrate produce a dynamic modulation of light in the near IR with almost perfect absorption (A > 93%). It is demonstrated that the resonant peaks of the hybrid absorber can be tuned in two different ways for any wavelength, with the crystallization fractions and the thickness of the dielectric. The influence of the metallic top layer thickness is also analyzed and demonstrated the fabrication error tolerance of the proposed absorber is demonstrated. Also analyzed is the influence of the thickness of the metallic top layer and tolerance to fabrication error of the proposed absorber is demonstrated. Finally, the physical mechanisms for the coupling of the electromagnetic field and the absorbed optical power in the structure proposed are presented and discussed. This study allows the beginning of the development of hybrid devices to control the absorption of light in the region of the electromagnetic spectrum used in optical communications.

Structures absorbing electromagnetic waves in the infrared spectral region are important optical components in key areas such as biosensors, infrared images, thermal emitters, and special attention is required for reconfigurable devices. We propose a three-dimensional metal-dielectric plasmonic absorber with a layer of PCM’s (Phase Change Materials). The phase shift effects of PCMs are numerically analyzed, and it is possible to obtain a shifting control of the resonant absorption peaks between the amorphous and crystalline states using the Lorentz–Lorenz relation. By using this empirical relation, we analyzed the peak absorption shift at intermediate phases between the amorphous and the crystalline. The geometric parameters of the structure with the PCM layer in the semi-crystalline state were adjusted to exhibit strong absorption for normal incidence. The effects of the oblique incidence on the absorption for the TM and TE polarization modes were also analyzed. Our results demonstrate that PCMs have great potential for reconfigurable nanophotonic devices.

We proposed and analyzed a planar narrow-band absorber based on a bi-layer metal/dielectric structure. The planar absorber uses the Fabry-Pérot resonance and the inherent loss of the metals, for maximum light absorption in the range of the electromagnetic spectrum visible to the near infrared. The absorption resonance peak can be shifted to other regions of the spectrum by varying the dielectric film thicknesses. It is also possible to control the absorption with the angle of incidence for TE and TM polarization modes. The high absorption (near unity) and the high tolerance to fabrication errors of the proposed absorber can be explored in a large number of optoelectronic devices.

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