  We experimentally achieve wave mode conversion and rainbow trapping in an
elastic waveguide loaded with an array of resonators. Rainbow trapping is a
phenomenon that induces wave confinement as a result of a spatial variation of
the wave velocity, here promoted by gently varying the length of consecutive
resonators. By breaking the geometrical symmetry of the waveguide, we combine
the wave speed reduction with a reflection mechanism that mode-converts
flexural waves impinging on the array into torsional waves travelling along
opposite directions. The framework presented herein may open new opportunities
in the context of wave manipulation through the realization of novel structural
components with concurrent wave conversion and energy trapping capabilities.
