Asymmetric lamb wave propagation in graded grating phononic crystal slabs

The unidirectional transmission of Lamb wave in low-frequency domains is realized by graded grating phononic crystal slabs This exotic phenomenon stems from the threshold frequency of the fundamental antisymmetric Lamb mode conversion to the fundamental symmetric Lamb mode is different at the different locations of the acoustic diode. This should be potentially significant in helping design chip-scale directional phononic devices.