Mitigating the effect of non-uniform loss on time reversal mirrors

Time reversal mirrors work perfectly only for lossless wave propagation. Here, the performance of time-reversal mirrors is quantitatively defined, and the adverse effect of dissipation on their performance is investigated. An application of the technique of exponential amplification is proposed to overcome the effect of dissipation in the case of uniform loss distributions, and, to some extent, in the case of non-uniform loss distributions. A numerical model of a star graph was employed to test the applicability of this technique on realizations with various random spatial distributions of loss. A subset of the numerical results are also verified by experimental results from an electromagnetic time-reversal mirror. The exponential amplification technique should improve the performance of emerging technologies based on time-reversed wave propagation such as directed communication and wireless power transfer.