Research

Dispersion curves of acoustic waves in ZX-cut LiNbO3

The direction of internal piezoelectric field in a Z-cut lithium niobate plate can be inverted by applying 22 kV/mm electric field across the plate. If the internal field is inverted only in periodically alternating zones, a set of periodic ferroelectric domains is formed. An ultrasonic wave that propagates through such periodic domains will show a stop-band if its wavelength is equal to the period of ferroelectric domains. We predicted existence of these stop bands with our Finite Element numerical simulation, and then confirmed this result in a series of experiments.

Dispersion curves of plate ultrasonic waves in ZX-cut LiNbO3, FEM simulation. The Fourier amplitude of acoustical displacement on the plate surface is proportional to the color temperature. Red lines represent acoustic modes that propagate in the x direction of the crystal. Blue color is background noise.

Dispersion curves of plate ultrasonic waves in ZX-cut LiNbO3, experimental data. White color represents Fourier amplitude of acoustical displacement of propagating modes. Dark grey color shows background acoustic noise.