Enhanced Faraday pattern stability with three-frequency driving.

We report experimental observations of enhanced stability of quasipatterns and superlattice patterns in a vertically oscillated, deep viscous fluid layer with the addition of a third driving frequency. With two-frequency driving in the ratios 4:5 and 6:7, 12-fold quasipatterns and type-I superlattice patterns appear, respectively, as a secondary instability for a range of relative phases and amplitudes. Addition of a small third-frequency component at twice the difference frequency, i.e., 4:5:2 and 6:7:2, shifts the region of stability for these patterns closer to onset. For a range of parameter values the stabilized patterns become the primary instability. The degree of stabilization is sensitive to the amplitude and relative phase of the third-frequency term in qualitative agreement with a recent symmetry based analysis of resonant three-wave interactions.