Trapped air metamaterials for ultrasonic sub wavelength imaging in water
1 Department of Informatics, Modeling, Electronics and Systems Engineering, University of Calabria, Via Pietro Bucci, 87036, Arcavacata di Rende (CS) Italy. {stefano.laureti, marco.ricci}@unical.it 2 School of Engineering, University of Warwick, Coventry, CV4 7AL, UK. {D.A.Hutchins, lorenzo.astolfi, r.watson.2, P.J.Thomas}@warwick.ac.uk 3 Department of Engineering, University of Perugia, Polo Scientifico Didattico di Terni, Via di Pentima 4, 05100, Terni, Italy. pietro.burrascano@unipg.it 4 School of Electronic and Electrical Engineering, University of Leeds, Leeds, LS2 9JT, UK. {L.Nie, s.freear}@leeds.ac.uk 5 School of Physics and Astronomy, University of St Andrews, St Andrews, KY16 9SS, UK. Ma297@st andrews.ac.uk. 6 Department of Mechanical, Material and Manufacturing Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD, UK. Adam.Clare@nottingham.ac.uk *Correspondence to Stefano Laureti (stefano.laureti@unical.it)