Fig. 6: Flexural wave pattern excited by a point source in a waveguide with gradient width.
From: Realization of ultrathin waveguides by elastic metagratings
a The out-of-plane displacement wave fields. The point source S is placed in the middle of waveguide. β refers to the guided-mode order. With the decrease of waveguide width, the guided-mode orders transit from β = 0, 2 to β = 0 smoothly. b The out-of-plane displacement w along the central line of the waveguide (the white dashed line in a). The waveform in the part of β = 0 is quite regular with a wavelength λ and has an almost constant amplitude. It is illustrated that the waveguide can rectify distorted incident waves to permit the single-mode.
