  We report on experimental and numerical implementations of devices based on
the negative refraction of elastic guided waves, the so-called Lamb waves.
Consisting in plates of varying thickness, these devices rely on the concept of
complementary media, where a particular layout of negative index media can
cloak an object with its anti-object or trap waves around a negative corner.
The diffraction cancellation operated by negative refraction is investigated by
means of laser ultrasound experiments. However, unlike original theoretical
predictions, these intriguing wave phenomena remain, nevertheless, limited to
the propagating component of the wave-field. To go beyond the diffraction
limit, negative refraction is combined with the concept of metalens, a device
converting the evanescent components of an object into propagating waves. The
transport of an evanescent wave-field is then possible from an object plane to
a far-field imaging plane. Twenty years after Pendry's initial proposal, this
work thus paves the way towards an elastic superlens.
