Flat lensing by graded line meta-arrays

Motivated by flat lensing effects, now commonplace utilizing negative refraction with finite slabs, we emulate negative refraction upon a graded line array. We do so in the setting of flexural waves on a structured Kirchhoff-Love elastic plate, as a paradigm in wave physics, that has direct extensions to electromagnetic and acoustic wave systems. These graded line arrays are geometrically simple and provide strong coupling from the array into the bulk. A thorough analysis of the dispersion curves, and associated mode structure, of these meta-arrays, supported by mode coupling theory, creates array-guided wave reversal and hybridization into the bulk that leads to striking wave control via generalized flat lensing.