Observation of asymmetric scattering in acoustic bianisotropic metagratings

Bianisotropic metagratings realize asymmetric wave transport by coupling pressure and velocity fields to redirect incident plane waves at an arbitrarily designed angle. The coupled fields simultaneously excite monopole and dipole scattering to redirect the acoustic energy from one grating diffraction mode to another. Given the bianisotropic coupling of the pressure and velocity, we systematically design a metagrating with Bloch wavevectors satisfying the wave-grating interaction in reciprocal space. The grating is designed using a finite element method to vary the dimensional parameters of each unit cell to maximize the scattering efficiency of the Bloch wavevector. We perform 2-D spatial Fourier analysis to verify that the scattering properties of the unit cell match the desired wave-grating interaction in reciprocal space. An experimental realization of the bianisotropic grating demonstrates the experimental results match the desired asymmetric scattering fields.Bianisotropic metagratings realize asymmetric wave transport by coupling pressure and velocity fields to redirect incident plane waves at an arbitrarily designed angle. The coupled fields simultaneously excite monopole and dipole scattering to redirect the acoustic energy from one grating diffraction mode to another. Given the bianisotropic coupling of the pressure and velocity, we systematically design a metagrating with Bloch wavevectors satisfying the wave-grating interaction in reciprocal space. The grating is designed using a finite element method to vary the dimensional parameters of each unit cell to maximize the scattering efficiency of the Bloch wavevector. We perform 2-D spatial Fourier analysis to verify that the scattering properties of the unit cell match the desired wave-grating interaction in reciprocal space. An experimental realization of the bianisotropic grating demonstrates the experimental results match the desired asymmetric scattering fields.