“…34 These configurations provide either a sequence of phase-shifted interferograms between different states of the vibrating object or a time averaged interferogram of the vibration pattern. More recently, Labrunie et al 35,36 proposed a so-called real time holographic interferometry (RT-HI) method based on anisotropic diffraction, i.e., the incident s-polarized light is diffracted as the p-polarized light and vice versa, in a Bi 12 GeO 12 (BGO) crystal. In this scheme, a refraction index grating is recorded by an overlapping signal and reference beam pulse linearly polarized along the same direction, at a certain instant of the object vibration.…”