M. Dubois, M. Farhat, E. Bossy, S. Enoch, S. Guenneau, P. Sebbah
The ability of left-handed materials to overcome the diffraction limit was first considered as one of the most exciting and challenging outcome of the negative-refraction concept. It was later recognized that understanding the time development of the super-lensing effect is crucial. Short pulse focusing was proposed recently as a new path to improve spatial resolution. Here, we show that Lamb wave at the surface of a structured thin plate is a paradigm to explore the dynamics of the super-lensing effect. We achieve broadband pulse focusing of bending waves at carrier frequencies below the first stop band in a 45{\deg}-tilted square array of circular air holes perforated in a Duraluminium thin plate. We find good agreement with a simple beam-lattice model. Finite-difference time-domain simulations confirm the role of lens resonances in pulse reconstruction. As time progresses, focal resolution improves down to 0.37 {\lambda}, in agreement with recent theoretical predictions.
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http://arxiv.org/abs/1303.3022
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