Metasurface-based acoustic hologram projectors fabricated with fixed microstructures can only generate the predesigned images at a single or few discrete frequencies. Here, a variety of acoustic holographic applications can be realized in broadband by a matched helical design of the tunable lossy acoustic metasurface (TLAM). The proposed TLAM unit is composed of a grating channel and an adjustable internal absorber to achieve the independent amplitude and phase modulations (APM) in a continuous frequency range. We demonstrate the excellent performance of the scattering-free anomalous refection by the APM method for tuning loss without foam materials. Then, the multi-plane acoustic holograms and the broadband holographic images are demonstrated by the flexible reconfigurations of one designed TLAM. Due to the compact design and the great flexibility, this proposal may be more practical to achieve the high-quality holograms with multi-scale fine manipulation and multiplexed acoustic communication with high information content.

中文翻译：

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具有独立振幅和相位调制的宽带可调谐有损超表面，用于声全息

使用固定微结构制造的基于超表面的声学全息投影仪只能在单个或几个离散频率下生成预先设计的图像。在这里，通过可调谐有损声学超表面 (TLAM) 的匹配螺旋设计，可以在宽带中实现各种声学全息应用。所提出的 TLAM 单元由光栅通道和可调内部吸收器组成，以在连续频率范围内实现独立的幅度和相位调制 (APM)。我们通过 APM 方法证明了无散射异常反射的优异性能，用于在没有泡沫材料的情况下调整损耗。然后，多平面声学全息图和宽带全息图像通过一个设计的 TLAM 的灵活重构来证明。