Phononic integrated circuitry and spin–orbit interaction of phonons

• Published in: Nature communications Vol. 10; no. 1; pp. 2743 - 7
• Main Authors: Fu, Wei, Shen, Zhen, Xu, Yuntao, Zou, Chang-Ling, Cheng, Risheng, Han, Xu, Tang, Hong X.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 21.06.2019; Nature Publishing Group; Nature Portfolio
• Subjects: 132/124; 142/126; 147/135; 639/166/987; 639/766/1130; 639/766/25/3927; Acoustic waves; Acoustics; Data processing; Gallium; Humanities and Social Sciences; Information processing; Integrated circuits; multidisciplinary; Optical waveguides; Phonons; Photonics; Propagation modes; Quantum phenomena; Sapphire; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-019-10852-3

High-index-contrast optical waveguides are crucial for the development of photonic integrated circuits with complex functionalities. Despite many similarities between optical and acoustic waves, high-acoustic-index-contrast phononic waveguides remain elusive, preventing intricate manipulation of phonons on par with its photonic counterpart. Here, we present the realization of such phononic waveguides and the formation of phononic integrated circuits through exploiting a gallium-nitride-on-sapphire platform, which provides strong confinement and control of phonons. By demonstrating key building blocks analogous to photonic circuit components, we establish the functionality and scalability of the phononic circuits. Moreover, the unidirectional excitation of propagating phononic modes allows the exploration of unconventional spin–orbit interaction of phonons in this circuit platform, which opens up the possibility of novel applications such as acoustic gyroscopic and non-reciprocal devices. Such phononic integrated circuits could provide an invaluable resource for both classical and quantum information processing. Developing planar phononic circuits analogous to photonic circuits are of interest to provide scalable advantages and complex manipulation of phonons. Here, the authors realize a phononic integrated circuit with a Gallium Nitride-on-sapphire platform, which provides strong confinement and control of phonons.