REVIEW OF SCIENTIFIC INSTRUMENTS, v.71, no.10, pp.3955 - 3957
Abstract
A simple interferometric method is described to measure the time-dependent deformation of piezoelectric bimorphs driven by ac voltage. Applying this method to a bimorph assembly used to measure viscoelastic forces in a surface forces apparatus, we find that a sinusoidal-shaped harmonic drive voltage generates sinusoidal deformation but that a triangular-shaped harmonic drive voltage fails to produce triangular-shaped deformation if the drive frequency exceeds 1/100 of the resonance frequency. Sinusoidal displacement amplitudes as small as 0.1 nm were resolved.