Acoustic Diode: Rectification of Acoustic Energy Flux in One-Dimensional Systems

We numerically demonstrate a simple one-dimensional model of an acoustic diode formed by coupling a superlattice with a strongly nonlinear medium. The first numerical observation is presented of a significant rectifying effect on the acoustic energy flux within particular ranges of frequencies. By studying the underlying rectifying mechanism and the parameter dependence of the rectifying efficiency, the effectiveness of the acoustic diode is proved despite its simplicity. We also briefly discuss possible schemes of the experimental realization of this model as well as devising more efficient models.

Figure 1

(a) The schematic illustration of the 1D model of the AD. (b) The dispersion relationship of linear band structure of the SL.

Figure 2

The spatial distributions of the time-averaged normalized energy densities in the system as acoustic wave incidents from the LB (a) and the RB (b), respectively. $E_1/E_0$ and $E_2/E_0$ are ratios of the energy densities of the FW and SHW to the incident wave, respectively.

Figure 3

(a) Total transmissions of energy flux versus the normalized amplitude of the incident wave. (b) Rectifying efficiency $T_{+}/T_{-}$ versus the strength of the incident wave for the parameters: $N=5$, ${\Gamma }_{\mathrm{III}}={10}^4$, $d_{\mathrm{III}}=15d_{\mathrm{I}}$ (circles), $N=5$, ${\Gamma }_{\mathrm{III}}={10}^4$, $d_{\mathrm{III}}=25d_{\mathrm{I}}$ (diamonds), $N=5$, ${\Gamma }_{\mathrm{III}}=5\times {10}^4$, $d_{\mathrm{III}}=15d_{\mathrm{I}}$ (squares), and $N=15$, ${\Gamma }_{\mathrm{III}}={10}^4$, $d_{\mathrm{III}}=15d_{\mathrm{I}}$ (triangles).