Enhanced stimulated Brillouin scattering in silicon slot subwavelength waveguides

The patterning of silicon with a period at the subwavelength scale has opened new degrees of freedom to control not only the propagation of light but also of sound. In this invited contribution, we will present our latest results on subwavelength-engineered silicon optomechanical waveguides. We harness subwavelength nanostructuration in a silicon slot waveguide to shape the distribution of the optical mode and maximize the coupling with the mechanical mode. Based on this approach, we demonstrate an enhanced Brillouin gain and a high tunability of the mechanical frequency.