title: Quasi-phase-matched backward second-harmonic generation by complementary media in nonlinear metamaterials.
abstract: High efficiency of the second-harmonic and sum-frequency generation can be obtained in optical superlattice by using the conventional quasi-phase-matched (QPM) method. Although this trick can be played on the acoustic wave, the media with negative nonlinear parameters are not common in acoustics. Furthermore, the QPM method used in acoustic metamaterials has been less studied. In this work, a protocol is provided to realize the QPM method by using nonlinear complementary media in acoustic metamaterials in order to obtain large backward second-harmonic generation. Compared with the conventional method, the method gains a broader bandwidth and can be used in both acoustic and electromagnetic waves.
authors.affiliation: Key Laboratory of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing 210093, People's Republic of China.
authors.forename: Li
authors.initials: L
authors.lastname: Quan
authors.forename: Xiaozhou
authors.initials: X
authors.lastname: Liu
authors.forename: Xiufen
authors.initials: X
authors.lastname: Gong
mesh_terms: D000162:Acoustics / Q000295:instrumentation*; D008420:Manufactured Materials; D009038:Motion; D017711:Nonlinear Dynamics; D013016:Sound