Fig. 7
From: Method for GHz optical helicity modulation by acoustic drum modes on a chip
Radial confinement mechanism. Propagation of Lamb waves with as small in-plane wave vector component \(k_r\) across the interface between two plates with different thickness \(d_\textrm{film}\ll d\). The side plots displays the wave profile at the left and right sides for frequencies \(f_m\) and \(f_m+\Delta f_m\), respectively, satisfying the boundary conditions at the top and back surfaces. The corresponding displacement anti-nodes are indicated by the dotted horizontal lines.
