Asymmetric frequency conversion with acoustic non-Hermitian space-time varying metamaterial

Abstract

Space-time modulated metamaterials support extraordinary rich applications, such as parametric amplification, frequency conversion and non-reciprocal transmission. However, experimental realization of space-time modulation is highly non-trivial, hindering many interesting physics that are theoretically predicted to be experimentally demonstrated. Here, based on the proposed virtualized metamaterials with software-defined impulse response, we experimentally realize non-Hermitian space-time varying metamaterials for efficient and asymmetric frequency conversion by allowing material gain and loss to be tailor-made and balanced in the time domain. In the application of frequency conversion, the combination of space-time varying capability and non-Hermiticity allows us to diminish the main band through gain-loss balance and to increase the efficiency of side band conversion at the same time. In addition, our approach of software-defined metamaterials is flexible to realize the analogy of quantum interference in an acoustic system with design capability. Applying an additional modulation phase delay between different atoms allows to control such interference to get asymmetric amplification in frequency conversion.

20 pages, 4 figures

References in corpus (5)

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• Parametric amplification and bidirectional invisibility in PT-symmetric time-Floquet systems
• Time-Varying Materials in Presence of Dispersion: Plane-Wave Propagation in a Lorentzian Medium with Temporal Discontinuity
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Cited by in corpus (15)

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• Roadmap on structured waves
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• Dissipative Spin-wave Diode and Nonreciprocal Magnonic Amplifier
• Percolation-induced PT symmetry breaking
• Harnessing the natural resonances of time-varying dispersive interfaces
• Construction of Non-Hermitian Parent Hamiltonian from Matrix Product States
• Stable-to-unstable transition in quantum friction
• Light controlled THz plasmonic time varying media: momentum gaps, entangled plasmon pairs, and pulse induced time reversal
• Chiral phase modulation and tunable broadband perfect absorber using the coherent cold atomic ensemble
• Symmetry-driven Phononic Metamaterials
• Parametric metasurfaces for amplified up-conversion of electromagnetic waves
• Space-time symmetry and nonreciprocal parametric resonance in mechanical systems
• Non-Hermitian Delocalization Induced by Residue Imaginary Velocity
• Interplay of non-Hermitian skin effect and electronic correlations in the non-Hermitian Hubbard model via Real-space dynamical mean field theory