We numerically investigated a dual-band metamaterial absorber based on the combination of plasmonic resonance and Fabry–Pérot (FP) resonance, which can achieve near-unity absorption for guided lasers. The absorber is constructed by a three-layer metal-insulator-metal (MIM) periodic configuration. In each unit cell, there is a gold-silicon cross on a thin silicon layer and a bottom nickel film. Numerical results show that, at normal incidence, the structure strongly absorbs light at wavelengths of 1.064 μm and 10.6 μm, with absorption rates higher than 94%. It is revealed that the two absorption peaks result from FP resonance in the thin silicon layer and plasmonic resonance in the cross, respectively. In addition, the absorber is polarization insensitive and is tolerant to the incident angle. The proposed combination of different resonances has the advantage of easily producing double absorption peaks with very large wavelength differences, and provides a new approach to the design of metamaterial absorbers.

The modulation of thermal radiation is essential for advanced photonic applications, offering a novel perspective for information carriers. However, current carriers are limited to a few discrete radiation states at isolated time points and cannot capture the entire dynamic process along the full temporal axis, resulting in substantial information loss. Here, we propose and experimentally validate a novel spatiotemporal modulation strategy that dynamically tailors emissivity across the entire temporal domain, where gentle and uniform modulation of atomic configurations enables the creation of entirely novel permittivity libraries. To realize flexible thermal radiation tailoring, we utilize an Ag–In ₃ SbTe ₂ (IST) interface atomic rearrangement metamaterial (ARM). As a dynamic optical control platform, ARM exhibits continuous spectral modulation with remarkably high amplitudes (64.74% in the 3- to 5-μm band and 73.94% in the 8- to 14-μm band), together with rich variations across the temporal domain to realize tailored infrared emissivity and infrared information encryption. This work establishes a unified framework for continuous, atomic-scale spatiotemporal control of thermal radiation, opening new pathways for spectral modulation and photonic information regulation in the time domain.

Metasurface absorbers are already used in many laser applications. To achieve laser stealth, a dual-band guided-laser absorber is presented in this paper. The absorber is composed of periodic silicon squares on a silicon film and a nickel layer. Under normal incidence, the absorber has two absorption peaks at wavelengths of 1.55 μm and 1.064 μm, with absorption rates higher than 94.4%. For wavelength-tunable 1.55 μm lasers with a large wavelength tuning range of ±50 nm, the absorption rate is still as high as 90%. Plasmonic resonance theory, as well as FDTD simulations, are used to design and study the absorber. It is found that the absorber is independent of the incident polarization and tolerant to the incident angle. The design method is flexible, and the absorber is easy to manufacture.

A quasi photonic crystal (QPC) dual-band absorber for laser stealth is designed and numerically studied. It consists of a defective two-dimensional photonic crystal on a thick Ni film. The defective photonic crystal is a continuous Ge layer with air holes, but some of the holes are periodically removed. Under a normal incidence that is perpendicular to the plane of the defects, the absorptivity can achieve 92.8% at the 1.064 μm wavelength and 93.2% at the 1.55 μm wavelength. Within large incident angles (80%. Additionally, the emissivity is as low as 5.8%~20.0% and 2.8%~5.8% in the 3–5 μm and 8–14 μm atmospheric windows. It is found that the introduced defects can couple the incidence into the structure and lead to spectral peaks (electromagnetic resonances) even without the bottom Ni film. With the help of the high-loss Ni film, the resonances are transformed into magnetic or/and electric modes of different orders. As a result, the QPC generates four absorption peaks. They are superimposed in pairs, resulting in enhanced absorption of the two laser wavelengths.