Acoustic effects on waveguide microstructures in silicon

Basic waveguide structures in anisotropic monocrystalline silicon medium are investigated for the existence of localized acoustic modes. The geometries of the structures were determined by technological methods and the practice of anisotropic etching, which guarantees reproducible high-quality structures in terms of geometric and crystallographic parameters. The acoustic effects were modeled by semi-analytical finite element method in the problems on eigenvalues and on the response to a harmonic traction source. Edge and surface localized modes were found. The spectral composition of the localized modes was interpreted on the basis of the surface acoustic wave slowness curves. Pseudomodes, highly localized leakage waves, were detected in a number of considered structures. The obtained results allow to evaluate promising geometrical configurations for further detailed study of the complete scope of dispersion properties of both single waveguides and their finite set.