Acoustic seminar | 13 November 2026

We theoretically and numerically demonstrate uniguided (UGR) and unicoupled (UCR) reso-
nances in an asymmetric acoustic metasurface. While a UGR radiates only to one side of the metasurface, its counter-propagating UCR counterpart radiates to both sides but can be excited only from one side. Using tem-
poral coupled-mode theory supported by finite-element simulations, we show that structural asymmetry enables intensity-flattened phase shifting with arbitrary transmittance in the lossless limit. We further demonstrate that thermoviscous losses introduce resonant intensity modulation and enable critical coupling. Under these condi- tions, perfect sound absorption occurs exclusively for excitation through a single scattering channel coupled to the UCR.

Main paper/arXiv, related to the seminar, and other references:
1) D. N. Maksimov, P. S. Pankin, D.-W. Kim, M. Song, C. Peng, and A. A. Bogdanov, Temporal coupled mode theory: From bound states in the continuum to uniguided resonances, Phys. Rev. B 112, 235303 (2025)
2) H. Li, W. Miao, Q. Du, P. Peng, and F. Liu, All-pass phase shifting achieved by acoustic unidirectional guided resonances, Appl. Phys. Express 17, 014002 (2023)
3) H. Li, M. Song, W. Zhang, Q. Du, P. Peng, and F. Liu, Perfect sound absorption induced by topological acoustic unidirectional guided resonance, Journal of Applied Physics 138, 233101 (2025)