Nonlinear optical response of gold–silver nanoplanets

The nonlinear optical properties of AuAg nanoplanets produced by ion implantation and subsequent irradiation in silica have been investigated by means of the single beam z-scan technique. These plasmonic nanosystems evidenced intense local-field enhancement effects, also theoretically demonstrated, that have a dramatic impact on their nonlinear optical response. In particular, the nonlinear absorption behavior was characterized by a tunable changeover from reverse saturable absorption to saturable absorption that can be induced by slightly varying the pump intensity. Owing to this, these systems offer the possibility to activate and observe phenomena otherwise not accessible in the intensity range that can be employed to study these materials without damaging the matrix.