Most multispectral compatible infrared camouflage devices primarily focus on achieving low emissivity but neglect environmental emissivity matching when environmental emissivity exceeds that of the devices, this creates a "low-emissivity exposure" risk. To address this issue, we develop a tunable multispectral compatible infrared camouflage device using phase change material In 3 SbTe 2 (IST). Simulation and experimental results demonstrate that in both the amorphous (aIST) and crystalline (cIST) states, the device achieves simulated plant infrared camouflage and ultra-low emissivity infrared camouflage within the atmospheric window bands (3-5 µm and 8-14 µm). To address thermal management, it utilizes two non-atmospheric window bands (2.5-3 µm and 5-8 µm) for heat dissipation. Additionally, laser stealth is realized at three specific wavelengths (1.064 µm, 1.55 µm, and 10.6 µm). In the visible spectrum, high absorptivity enables effective visible light camouflage. Adjusting the geometric parameters of top layer structure enables color variation. This work not only highlights potential applications in reversible switching, reconfigurable imaging, and dynamic coding using IST but also offers an effective strategy to counter multispectral detection technology.

In recent years, dynamically tunable structural color has attracted great interest. Here, we introduce the guided-mode resonance (GMR) filter and the phase-change material Sb₂S₃ to design a reflective optical metasurface to produce tunable structural color, in which the combination of the GMR filter, with narrow resonant wavelength, and the Sb₂S₃, with a much larger bandgap and higher refractive index, helps to produce high-quality tunable structural color. The simulation results indicate that through the phase transition between the amorphous and crystalline states of Sb₂S₃, the proposed metasurface can generate tunable structural color that can be perceived by the naked eye. Furthermore, the metasurface can sensitively sense environmental changes through changes in structural color. This work provides a new method for realizing dynamically tunable structural color, and paves the way for the application of controllable structural color in dynamic displays, optical stealth, colorimetric sensing, and other fields.

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.

Based on the novel concept of a fully-digitized module, we employ a forward-designed-assisted inverse design method to design a nonvolatile reconfigurable mode generator and an optical circulator, assisted with a phase change material. The mode generator can selectively output different modes. The fundamental transverse electric (TE ₀ ) or TE ₁ modes can be selectively generated when the TE ₀ mode is launched in the input port. The mode generator with an effective footprint of 2.4 μm × 16 μm exhibits the simulated insertion losses of less than 1.0 dB and the simulated crosstalks of lower than –19.0 dB for both the TE ₀ and TE ₁ modes from 1540 nm to 1560 nm. The optical circulator enables the light unidirectional propagation. Photons can be precisely routed from each input port to one adjacent output port in clockwise or counterclockwise directions. The simulated results indicate that the circulator with an effective footprint of 24 μm × 24 μm, can provide both the simulated insertion losses of less than 0.8 dB and the simulated crosstalks of lower than –16.3 dB from 1540 nm to 1560 nm in both clockwise and counterclockwise directions. The fabrication tolerances caused by the expansion or contraction of the etched pattern contour are also investigated. In principle, the proposed frameworks can be extended to an arbitrary number of ports for designing mode generators and optical circulators.

A subwavelength fine-structured silicon–gold metagrating was designed for realizing mid-infrared (mid-IR) narrowband absorbers. The metagrating consisted of a silicon grating on the stack of a gold film and a quartz substrate. The silicon grating consisted of two periodically arranged silicon strips in each unit cell. The numerical results reveal that perfect absorption of the traverse-magnetic (TM) polarized light at a wavelength of 4.071 μm can be achieved, with an absorption rate of ~99.2% and an absorption full-width at half-maximum (FWHM) bandwidth of ~31 nm. Thus, the proposed structure is useful for the spectral control of mid-IR signals. When used as a refractive index sensor, the structure has a measuring range of 1.0–2.0 with a quasi linear response, with a figure of merit (FOM) of ~103.