Figure | Working principle of the non-volatile switchable infrared stealth metafilm. (IMAGE)

Light Publishing Center, Changchun Institute of Optics, Fine Mechanics And Physics, CAS

Figure | Working principle of the non-volatile switchable infrared stealth metafilm.

Caption

a, Schematic diagram of the bilayer metafilm and the transition mechanism of GST between different states. The infrared stealth metafilm is based on the bottom metal Mo layer and the top phase change material GST layer. When the temperature exceeds the crystallization temperature Tc, the GST will gradually change from amorphous state to the crystalline state, and once the temperature exceeds the melting temperature Tm, after rapid annealing, the GST can change back to the amorphous state. b, The infrared radiation characteristics of the sample for the two states of GST. When the GST is in the amorphous state, the low average emissivity of the film in the atmospheric window band enables infrared stealth. Meanwhile, within non-atmospheric window band, it demonstrates a high average emissivity and facilitates radiative heat dissipation; When the state of GST changes to crystalline, the average emissivity of the structure in 8-14 μm exceeds 0.67, and the structure turns to the non-stealth state. (c), Demonstration of the different infrared emissivity of the samples before and after the phase transition. In (c), The temperature of the samples with both amorphous (sample A) and crystalline states (sample B) of GST are measured under the background temperature of 30℃, 50℃, 75℃ and 100℃, respectively. Simultaneously, a silicon substrate (sample C) of comparable size is placed as a reference. It can be intuitively found that compared with the sample in the crystal state, when GST is in the amorphous state, the temperature of the sample is significantly lower than the background temperature. Furthermore, as the background temperature increases, there is a continuous increase in temperature difference between samples in the two states. When the background temperature reaches 100℃, the temperature difference between the two samples is as high as 28℃, which is a very intuitive demonstration of the huge change in the infrared radiation characteristics of the sample after the phase transition.

Credit

by Cong Quan, Song Gu et al.

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