Space-time modulated phononic crystals
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To break reciprocity of acoustic wave propagation, non-Hermitian systems based on three physical mechanisms have been considered in recent years: (i) nonlinear propagation in nonsymmetric layered media causing rectification of energy flux due to nonreciprocal energy dissipation at harmonic frequencies; (ii) introduction of a static bias; and (iii) time-varying (locally time-controlled or time-programmable properties) or space-time modulation of effective properties of acoustic materials. Here we propose to investigate space-time modulated (STM) phononic crystals. One advantage of STM metamaterials lies in the introduction of additional time/frequency and space/wavenumber scales associated with the modulation which may couple to wave frequency/wavenumber and metamaterial resonance frequency. The broad spectrum of these interactions eventually associated with multiphysical and/or nonlinear effects constitutes a ris- ing field of research for wave engineering..
Articles related to this topic:
1 - Palacios, J., Calderin, L., Chon, Al., Frankel, I., Alqasimi, J., Allein, F., Gorelik, R. , Lata, T., Curradi, R., Lambert-Milak, G., Oke, A., Smith, N., Abi Ghanem, M., Lucas, P., Boechler, N., & Deymier, P.,
Temperature-Controlled Spatiotemporally Modulated Phononic Crystal for Achieving Nonreciprocal Acoustic Wave Propagation.
The Journal of the Acoustical Society of America 151, 3669 (2022). PDF
2 - Tessier Brothelande, S., Croënne, C., Allein, F., Vasseur, J. O., Amberg, M., Giraud F., & Dubus, B.,
Experimental evidence of nonreciprocal propagation in space-time modulated piezoelectric phononic crystals.
Advanced Applied Physics Letters 123, 201701 (2023). PDF
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