Phoxonic Hybrid Superlattice

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• 作者：Elena Alonso-Redondo ; Hannah Huesmann ; El-Houssaine El Boudouti ; Wolfgang Tremel ; Bahram Djafari-Rouhani ; Hans-Juergen Butt ; George Fytas
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：June 17, 2015
• 年：2015
• 卷：7
• 期：23
• 页码：12488-12495
• 全文大小：396K
• ISSN：1944-8252

文摘

We studied experimentally and theoretically the direction-dependent elastic and electromagnetic wave propagation in a supported film of hybrid PMMA (poly[methyl-methacrylate])-TiO₂ superlattice (SL). In the direction normal to the layers, this one-dimensional periodic structure opens propagation band gaps for both hypersonic (GHz) phonons and near-UV photons. The high mismatch of elastic and optical impedance results in a large dual phoxonic band gap. The presence of defects inherent to the spin-coating fabrication technique is sensitively manifested in the band gap region. Utilizing Brillouin light scattering, phonon propagation along the layers was observed to be distinctly different from propagation normal to them and can, under certain conditions (SL thickness and substrate elasticity), reveal the nanomechanical properties of the constituent layers. Besides the first realization of unidirectional phoxonic behavior, hybrid (soft鈥揾ard) periodic materials are a promising simple platform for opto-acoustic interactions and applications such as filters and Bragg mirrors.