Imaging of surface acoustic waves

Active chiral control of GHz acoustic whispering-gallery modes

“…The CW/CCW Fourier amplitude ratios are R and ∼3600 m/s for the surface waves travelling across the disk. These velocities lie between the Rayleigh wave velocities in silica and silicon, as expected 21,22 .…”

Surface acoustic waves in two-dimensional periodic elastic structures

“…This ultrasonic method has been developed by Vines, Hauser, and Wolfe for characterizing the propagation of coherent surface acoustic waves in anisotropic media. 13 By rotating the sample about an axis normal to the surface, the propagation of waves along any direction in the surface can be recorded. When point-focus transducers are used, ultrasonic waves with a broad angular distribution of wave vectors are excited, so the measurement reveals the acoustic energy flux or group velocity along a given direction.…”

“…We also plot the stop band distribution of both the surface and bulk acoustic waves which would be observable in an ultrasound imaging experiment. 8,12,13 II. FORMULATION We assume the system to be an elastic continuum composed of a periodic array of cylinders of material A embedded in a background material B.…”

Scanning ultrafast Sagnac interferometry for imaging two-dimensional surface wave propagation

“…Surface motion or strain-induced refractive index changes, in particular, provide suitable mechanisms for the optical sensing of surface acoustic waves ͑SAWs͒ on solids with visible optical wavelengths. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Developments in this field have been driven by the possibilities for nondestructively monitoring SAW propagation for the characterization of the elastic properties of isotropic and anisotropic materials, the mechanical properties of thin films, and SAW devices such as filters. [15][16][17][18][19][20] Moreover, the imaging of SAW propagation on crystals is of fundamental interest because of the complex focusing patterns that arise from the variation of sound velocity with propagation direction.…”

“…[15][16][17][18][19][20] Moreover, the imaging of SAW propagation on crystals is of fundamental interest because of the complex focusing patterns that arise from the variation of sound velocity with propagation direction. [1][2][3][4][5][6] Various optical detection techniques for SAW have been proposed: knife-edge techniques, [13][14][15] interferometric techniques, [4][5][6]17,18,21,22 holographic techniques, 7,8,[10][11][12]15 Schlieren techniques, 16 diffraction techniques, 19 and Brillouin scattering techniques. 15,23 Full information on the SAW field for a general broadband wave disturbance can be most simply obtained by real time detection, and the knife-edge and interferometric techniques have proved most successful for this.…”