Active chiral control of GHz acoustic whispering-gallery modes

作者：Sylvain Mézil, Kentaro Fujita, Paul H. Otsuka, Motonobu Tomoda, Matt Clark, Oliver B. Wright, Osamu Matsuda · 发表于：Applied Physics Letters · 年份：2017 · DOI：10.1063/1.4994886 · 被引用次数：11 · 研究领域：Acoustic Wave Resonator Technologies、Mechanical and Optical Resonators、Photonic and Optical Devices

We selectively generate chiral surface-acoustic whispering-gallery modes in the gigahertz range on a microscopic disk by means of an ultrafast time-domain technique incorporating a spatial light modulator. Active chiral control is achieved by making use of an optical pump spatial profile in the form of a semicircular arc, positioned on the sample to break the symmetry of clockwise- and counterclockwise-propagating modes. Spatiotemporal Fourier transforms of the interferometrically monitored two-dimensional acoustic fields measured to micron resolution allow individual chiral modes and their azimuthal mode order, both positive and negative, to be distinguished. In particular, for modes with 15-fold rotational symmetry, we demonstrate ultrafast chiral control of surface acoustic waves in a micro-acoustic system with picosecond temporal resolution. Applications include nondestructive testing and surface acoustic wave devices.