Triplon modes of puddles

Free fluctuations of the contact line of large drops (puddles) of wavelength lambda >kappa(-1), the capillary length, cannot be seen on a solid substrate because even a small but finite hysteresis is enough to block these slow modes. We show here that vertical vibrations of the substrate (at frequency omega(E), acceleration Lambda) above a threshold amplitude Lambda(c) release the line and excite contour oscillations (triplons). We observe harmonic modes and parametric excitations at omega(E)/2. We construct the phase diagram (Lambda,omega(E)) of these subharmonic modes and we study their growth dynamics: they slow down near the threshold of the contour instability.