Precise control of ultrasonic acoustic waves with frequencies f ≳ 20 kHz is useful in a range of applications from ultrasonic scanners to nondestructive testing and consumer haptic devices. A spatial sound modulator (SSM) is the acoustic analogy to the spatial light modulator (SLM) in optics and is highly sought after by acoustics researchers. A spatial sound modulator is constrained by very distinct practical conditions. Namely, it must be a reconfigurable device which modulates sound arbitrarily from a decoupled source. Here a reflective phase modulating device is realized, whose local units can be tuned to imprint a phase signature to an incoming wave. It is manually reconfigurable and consists of 1024 rigidly ended square waveguides with sliding bottom surfaces to provide variable phase delays. Experiments demonstrate the ability of this device to focus ultrasonic waves in air at different points in space, generate accurate pressure landscapes, and perform multiplane holography. Moreover, thanks to the subwavelength nature of the unit cells, this device outperforms state‐of‐the‐art phased‐array transducers of the same size in the quality and energy distribution of generated acoustic holographic images. These results pave the way for the construction of electronically controlled reflective SSMs.

中文翻译：

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用于空气中超声波的手动可重构反射空间声音调制器

频率为f的超声波的精确控制kHz 20 kHz在从超声波扫描仪到无损测试和消费者触觉设备的一系列应用中非常有用。空间声调制器（SSM）是光学领域中与空间光调制器（SLM）的声学类比，受到声学研究人员的追捧。空间声音调制器受到非常不同的实际条件的限制。即，它必须是可重新配置的设备，用于从解耦的源中任意调制声音。在此实现了反射式相位调制装置，该反射式相位调制装置的局部单元可以被调节为将相位标记压印到入射波上。它是可手动重新配置的，由1024个带有滑动底面的刚性端部方形波导组成，以提供可变的相位延迟。实验证明了该设备能够将超声波聚焦在空间中不同位置的空气中，生成准确的压力景观，并执行多平面全息照相。此外，由于单位晶格的亚波长特性，该设备在生成的声全息图像的质量和能量分布方面要优于同等尺寸的最新相控阵换能器。这些结果为电子控制反射式SSM的构造铺平了道路。