Total conversion between the longitudinal and transverse waves by an ultrathin elastic metamaterial plate with U-shaped slits

Abstract In this work, we propose an elastic metamaterial plate made by an aluminum block tailored with a row of periodic pair of U-shaped slits. Total conversion between longitudinal and transverse modes can be achieved by the metamaterial plate. The conversion is induced by an oblique dipolar resonance, not relying on the Fabry–Pérot resonance or the design of effective parameters. The plate’s thickness can be orders smaller than the working wavelength, showing good potential in practical applications.