On the role and choice of source polarization in time reversal focusing of vector fields

Time reversal is a well-known method to focus a wave-field into complex unknown/known media. In this letter, we show that when applying time reversal to vector fields, a proper choice of the test source's polarization allows definite advantages as compared to the usual approach of using an a priori fixed polarization. As a matter of fact, by so doing, one can not only focus the target point, but also obtain a field distribution that better accommodates some other requirements (e.g., minimizes sidelobe level). To exploit this possibility, we propose a simple and effective optimization strategy and assess it in case of focusing transverse electric (TE) fields into 2-D scenarios.