6D-2 Wavenumber Domain Analysis of Two-Dimensional SAW Images Captured by Phase-Sensitive Laser Probe System

This paper is aimed at demonstrating how the wavenumber domain analysis of two-dimensional images captured by phase-sensitive laser probe systems is effective in selective characterisation of unwanted responses of RF SAW devices. The authors have recently reported the development of a high-speed and phase-sensitive laser probe system. Since the distance between two adjacent points of measurement is constant and calibrated, the 2D fast Fourier transform (FFT) and inverse FFT are directly applicable to the measured SAW field for the wavenumber domain analysis. This analysis offers various additional information of spurious signals. Effectiveness of the wavenumber domain analysis is demonstrated through the characterisation of spurious resonance modes and scattered non-guided modes appearing in SAW resonators fabricated on ST quartz substrate