Beyond the constraints of conservative systems, altering wave propagation frequency emerges as a crucial factor across diverse physical domains. This Letter demonstrates bi-directional asymmetric frequency conversion -- either upward or downward -- depending on the excitation direction in the elastic domain, moving beyond uni-directional approaches. We numerically and experimentally demonstrate its practical realization in a model system of cylindrical beam crystals, a type of granular crystal characterized by intrinsic local resonance. This novel wave transport mechanism operates through the interplay of nonlinear contact, spatial asymmetry, and the coupling of local resonance. Thanks to the proposed highly tunable architecture, we demonstrate various ways to manipulate wave transport, including tunable frequency conversion. Given that the local resonance we employ exemplifies avoided crossings (i.e., a strong coupling effect), our work may inspire investigations into diverse physical nonlinear domains that support material/structural resonance.
Low-loss phononic integrated circuits based on a silicon nitride-lithium niobate platform
Bradley Department of Electric and Computer Engineering, Virginia Tech（弗吉尼亚理工大学电气与计算机工程布拉德利系）；Department of Electrical and Computer Engineering, University of Virginia（弗吉尼亚大学电气与计算机工程系）；Department of Physics and Center for Quantum Information Science and Engineering (VTQ), Virginia Tech（弗吉尼亚理工大学物理系及量子信息科学与工程中心）
Cryogenic enhancement of phononic four-wave mixing in AlScN/SiC
Center for Integrated Nanotechnologies, Sandia National Laboratories（桑迪亚国家实验室集成纳米技术中心）；Microsystems Engineering, Science, and Applications, Sandia National Laboratories（桑迪亚国家实验室微系统工程、科学与应用）；Department of Electrical and Systems Engineering, University of Pennsylvania（宾夕法尼亚大学电气与系统工程系）；Electrical, Computer and Energy Engineering, University of Colorado, Boulder（科罗拉多大学博尔德分校电气、计算机与能源工程学院）
A deep dive into Tollmien-Schlichting wave control via passive wall deformations: The battle between local and downstream stabilization, lessons learned, and implications for phononic subsurfaces
University at Buffalo (SUNY)（布法罗纽约州立大学）；Purdue University（普渡大学）
Alignment-free ultra-broadband parametric frequency conversion in lead-halide perovskites
Institute of Science and Technology Austria (ISTA)（奥地利科学技术研究所）；International Laser Centre（国际激光中心）；RCQI, Institute of Physics SAS（斯洛伐克科学院物理研究所量子凝聚态与量子信息研究中心）；King Abdullah University of Science and Technology（阿卜杜拉国王科技大学）；School of Materials Science and Engineering (MSE), Nanyang Technological University（南洋理工大学材料科学与工程学院）；Center for Renewable Energy and Storage Technologies (CREST), Division of Physical Science and Engineering (PSE), King Abdullah University of Science and Technology（阿卜杜拉国王科技大学物理科学与工程学部可再生能源与储能技术研究中心）
Temporal refraction and reflection in modulated mechanical metabeams: theory and physical observation
University of Missouri（密苏里大学）；Ningbo University（宁波大学）；City University of New York（纽约市立大学）；Graduate Center, City University of New York（纽约市立大学研究生中心）；Peking University（北京大学）
