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In this paper, we propose a broadband infrared stealth metamaterial absorber based on an improved metal-dielectric-metal structure where its top pattern consists of multi-layers. The structure uses high-temperature resistant materials instead of traditional low melting point precious metals and achieves selective thermal radiation in the infrared band. The study shows that with the increase of the number of layers, the absorption peak and bandwidth of the non-atmospheric window band expands. When the thickness of the structure is five layers, it can match well with the atmospheric absorption spectra. The polarization sensitivity and infrared stealth performance at different temperatures of the structure with five-layer are studied in detail. Compared with black body, the selective thermal emitter maintains radiation reduction rates greater than 80% in MWIR and LWIR regions. The high temperature resistant heat emitter proposed by us can be used in spectrally selective thermal radiation, thermal management and thermal camouflage, which has a very promising application prospect. [ABSTRACT FROM AUTHOR]

Actively tunable metasurfaces have widespread applications in optics from light modulation, beam steering to LiDAR and many others. Recently, lithium niobate (LN) based metasurfaces have attracted significant attention for their great potentials in integrated electro-optically tunable metadevices. However, the hardness and chemical inactivity of LN make it difficult to process, which severely limits the quality (Q) factors and performance of LN based metasurfaces. In this paper, a type of high Q etchless LN resonant metasurface is experimentally demonstrated. The metasurface shows a measured Q factor of 563 around the telecom wavelength and even higher Q factors are expected to be realized using similar designs in the future. This work represents an important progress for LN resonant metasurfaces and paves the way for the development of high performance electro-optically tunable LN metadevices. • Demonstrate a type of high-Q LN resonant metasurface in telecom wavelength range. • Uses a dielectric-loaded design with subwavelength patterns. • The LN is etchless to avoid the fabrication difficulty. • The measured Q factor of 563 is almost one order higher than the previous work. • Paves the way for the development of high performance EO tunable LN metadevices. [ABSTRACT FROM AUTHOR]