Pros and cons of recording of long strain waves in polymer waveguides by means of digital holography in transmission and reflection configurations and by piezoelectric transducers

We present an analysis of the advantages and disadvantages of recording and monitoring of nonlinear strain waves in a solid waveguide made of a nonlinearly elastic material (polystyrene) using three techniques: off-axis digital holography with observation ‘in-transmission’ and ‘in-reflection’ and acoustical diagnostics utilizing piezoelectric transducers. Holographic ‘in-transmission’ recording was shown to provide more reliable determination of wave parameters owing to both higher resolution and sensitivity to longitudinal waves only. When monitoring the wave process by piezoelectric sensors attached to the lateral surface of the waveguide, the sensor sensitivity to shear waves did not allow us to isolate the contribution of longitudinal waves in a prolonged input part of the waveguide.