Abstract

The nonlinear optomechanical phenomenon known as Stimulated Brillouin Scattering (SBS) has attracted much recent attention in photonics, having a diverse range of important applications in such areas as sensing, narrow-linewidth sources, microwave photonics and spectroscopy [1]. Generating and using SBS is challenging in many platforms because the conditions for optical confinement (high refractive index of the core) are often at odds with the conditions for guidance of the acoustic wave, which are that the core material is mechanically compliant [2]. However there exists a class of materials – metals – that are both mechanically “soft”, and can also be used to strongly confine the optical field, in the form of Surface Plasmon Polaritons (SPPs). One might assume that the high optical loss and associated short propagation constants of SPPs indicate that these structures are not conducive to SBS. On the other hand, surface plasmons are associated with strong optical field gradients, which might be expected to assist SBS; in addition it is expected that a strong overlap between optical and acoustic modes can be achieved. The question of whether or not SBS can be harnessed, and useful gain measured, is therefore an open and interesting physical problem.

© 2017 IEEE