In this paper, we design a sandwich multilayer film structure based on phase-change material Ge2Sb2Te5 (GST). In the visible band, based on the amorphous and crystalline state of GST, visible light absorption and color camouflage can be achieved. The transition between the amorphous and crystalline state of GST by temperature modulation can achieve dynamic color tuning without affecting the absorption. In the infrared band, the structure can realize the infrared camouflage function in the amorphous and crystalline states, which means that it has a higher reflection function in the infrared band. Therefore, the multilayer film based on the phase-change material GST has a simple structure and mature preparation process, which can be effectively compatible with the visible-infrared band to realize the multi-functions of color camouflage, visible light absorption and infrared camouflage.
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.
A temporal femtosecond pulse shaping device, based on all-diffractive method, is designed for arbitrary waveform generation. The key components of the device are micro-gratings arranged in line. By changing the period and phase pattern of each grating, the diffraction angle, phase and amplitude of the first order diffraction light can be modulated. Experimental results are consistent well with simulation results, which indicate that arbitrary temporal waveforms can be gained by using micro-gratings array. Additionally, the configuration of the device allows for multiple outputs and can operate over a large wavelength range from ultraviolet to infrared pulse.
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