Characterisation of the polarisation state of embedded piezoelectric transducers by thermal waves and thermal pulses

Abstract. In this work, we apply the thermal wave method and the thermal pulse method for non-destructive characterisation of the polarisation state of embedded piezoelectric transducers. Heating the sample with a square-wave modulated laser beam or a single laser pulse leads to a pyroelectric current recorded in the frequency or time domain, respectively. It carries information about the polarisation state. Analytical and numerical finite element models describe the pyroelectric response of the piezoceramic. Modelling and experimental results are compared for a simple lead–zirconate–titanate (PZT) plate, a low-temperature co-fired ceramics (LTCC)/PZT sensor and actuator, and a macro-fibre composite (MFC) actuator.