Localizations in fractal drums: An experimental study

The low-frequency eigenmodes of a fractal drum are studied through experime ntal observation of the acoustical resonances of a fractal-shaped liquid cr ystal film. The resonance frequencies agree with the numerical predictions far the Laplacian eigenvalues in the fractal domain with Dirichlet boundary conditions. The amplitude distribution of the modes is detected by scannin g the excitation position. Several modes are found to be localized in agree ment with numerical predictions. Two types of localization related to "stro ng" and "weak" localization mechanisms are observed in this system. This Le tter presents the first direct experimental study of localized modes in fra ctal geometries.