title: Acoustic wave science realized by metamaterials.
abstract: Artificially structured materials with unit cells at sub-wavelength scale, known as metamaterials, have been widely used to precisely control and manipulate waves thanks to their unconventional properties which cannot be found in nature. In fact, the field of acoustic metamaterials has been much developed over the past 15 years and still keeps developing. Here, we present a topical review of metamaterials in acoustic wave science. Particular attention is given to fundamental principles of acoustic metamaterials for realizing the extraordinary acoustic properties such as negative, near-zero and approaching-infinity parameters. Realization of acoustic cloaking phenomenon which is invisible from incident sound waves is also introduced by various approaches. Finally, acoustic lenses are discussed not only for sub-diffraction imaging but also for applications based on gradient index (GRIN) lens.
authors.affiliation: Department of Naval Architecture and Ocean Engineering, Mokpo National Maritime University, Mokpo, 58628 Republic of Korea.|Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673 Republic of Korea.
authors.forename: Dongwoo
authors.initials: D
authors.lastname: Lee
authors.affiliation: Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673 Republic of Korea.
authors.forename: Duc Minh
authors.initials: DM
authors.lastname: Nguyen
authors.affiliation: Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673 Republic of Korea.|Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673 Republic of Korea.
authors.forename: Junsuk
authors.initials: J
authors.lastname: Rho
keywords: Cloaking; Gradient index; Metamaterials; Sub-diffraction imaging; Sub-wavelength