Two‐Bit Coding Realization of Acoustic Parity Metasurfaces

Parity is an important concept in physics, yet its crucial role in controlling optical and acoustic fields has long been overlooked. Herein, the viewpoint of parity as a novel degree of freedom in precisely controlling wave behavior is proposed and demonstrated, originating from the analytical proof for the universality of the parity high‐order diffraction effects in phase gradient metasurfaces. This unique parity diffraction phenomenon is applied to acoustic coding metasurfaces to achieve a dual process for the waveform reshaping and energy redistribution of plane waves. Analytical calculations, numerical demonstrations, and acoustic experiments verify the feasibility of this new parity paradigm in realizing digital information encoding. This work has potential applications in underwater communications and information anticounterfeiting security.