Solar energy is a clean and renewable energy source and solves today’s energy and climate emergency. Near-perfect broadband solar absorbers can offer necessary technical assistance to follow this route and develop an effective solar energy-harvesting system. In this work, the metamaterial perfect absorber operating in the ultraviolet to the near-infrared spectral range was designed, consisting of a periodically aligned titanium (Ti) nanoarray coupled to an optical cavity. Through numerical simulations, the average absorption efficiency of the optimal parameter absorber can reach up to 99.84% in the 200–3000 nm broadband range. We show that the Ti pyramid’s localized surface plasmon resonances, the intrinsic loss of the Ti material, and the coupling of resonance modes between two neighboring pyramids are highly responsible for this broadband perfect absorption effect. Additionally, we demonstrate that the absorber exhibits some excellent features desirable for the practical absorption and harvesting of solar energy, such as precision tolerance, polarization independence, and large angular acceptance.

Infrared selective emitters are attracting more and more attention due to their modulation ability of infrared radiance, which provides an efficient ability to blend objects into the surrounding environment. In this paper, an Ag/ZnS/Si/Ag/Si multilayered emitter is proposed by virtue of impedance matching as well as Fabry-Perot cavity effect to achieve selective radiation in the infrared band. The emissivity of the fabricated selective emitter is measured to be ε_3–5μm = 0.16 and ε_8–14μm = 0.23 in the atmosphere windows, respectively, meeting the requirements of infrared stealth. Meanwhile, the emissivity at the non-atmospheric window (5–8 μm) is as high as 0.78, which allows efficient heat dissipation to achieve radiative cooling. Furthermore, the selective emitter maintains excellent stealth performance until 350 °C, indicating its good heat resistance and dissipation at medium temperature. The proposed emitter with spectral selectivity provides a new strategy for the facile fabrication of mid-/low-temperature infrared stealth devices.

Significant advancements have been made in multiband infrared detectors, making the integration of multiband infrared compatibility with stealth capabilities essential for counteracting multiband infrared detection. This paper introduces a multiband metamaterial selective thermal emitter featuring an Ag/TiO₂/Ag nanosandwich structure capable of achieving both infrared and laser-compatible stealth. Through the use of inherent absorption in lossy dielectrics, magnetic resonance properties of MIM structures, and coupling of propagating surface plasmons with Fabry-Pérot cavity resonances, the multiband infrared stealth compatibility is effectively controlled. The fabricated samples show low emissivity (ɛ _3-5µm = 0.09, ɛ _8-14µm = 0.54) in atmospheric windows, contributing to infrared stealth invisibility, and high emissivity (ɛ _2.5-3µm = 0.50, ɛ _5-8µm = 0.69) in non-atmospheric windows, facilitating radiative cooling. The sample exhibits lower surface temperatures compared to aluminum thin films, demonstrating superior thermal management. Additionally, high absorption at 1.55 µm (ɛ = 0.86) and 10.6 µm (ɛ = 0.94) is achieved due to the interference of the TiO₂ layer and its inherent loss characteristics, facilitating laser camouflage. Moreover, this study centers on a multiband selective thermal emitter based on a metasurface structure, offering significant potential for multiband infrared camouflage technology.

With the rapid advancement of detection technologies, the demand for multi-band compatible camouflage solutions has significantly increased. In this study, we propose a flexible meta-coating based on a polyimide (PI) substrate, featuring a double Fabry–Perot cavity for effective camouflage across visible–near-infrared laser-infrared bands. The visible color of the structure can be tuned by adjusting the thickness of the top dielectric layer, enabling selective reflection of specific light wavelengths. In the infrared atmospheric window, the multilayer film exhibits low average emissivity (ε_3–5μm = 0.16, ε_8–14μm= 0.18), providing efficient thermal camouflage. Conversely, in the non-atmospheric infrared window, the film shows higher emissivity (ε_5–8μm = 0.63), facilitating effective radiation heat dissipation. Experimental results show that the surface temperature of the structure is 183.5°C when heated to 210°C, which is 17°C lower than that of an Al wafer under the same conditions. Additionally, the structure demonstrates high low reflectivity at 1.06 μm (ε_1.06μm = 0.94) and 1.55 μm (ε_1.55μm = 0.99), making it suitable for visible light-laser-infrared. This work provides a feasible solution for large-area, low-cost, heat-resistant, and multispectral-compatible camouflage, with potential applications in military applications.

Metals are crucial for solar energy applications, but their highly reflective surfaces limit solar energy absorption. The difficulty in manufacturing an ideal light-absorbing structure limits the incorporation of anti-reflective characteristics in metals. In this study, a femtosecond laser method was introduced to form micro-nano structures in metals, enhancing absorption by the application of silver nanoparticles and resulting in solar absorption rates of 97.2%, 98.3%, and 98.9% for aluminum, titanium, and steel, respectively. The solar reflectance was reduced by 82.3%, 62.6%, and 79.2%, respectively, compared to bare metal. Photothermal conversion and deicing tests verified a more efficient photothermal conversion ability in the composite micro-nanostructure surface. Compared to bare metal, the structure has more than twice the solar absorption efficiency and improves the deicing efficiency by 132%. The resultant material exhibits high photothermal conversion and deicing efficiencies, enhancing its potential for solar energy applications, particularly in photothermal, photovoltaic, and thermal solar technologies.