Abstract
Retrieval of the amplitude and phase of electromagnetic waves made digital holographic microscopy (DHM) capable of revealing morphological details at ultrahigh resolution in the order of a few nanometers only and precisely measuring the refractive index across a sample (e. g. cell or neuron). In short, DHM added a new dimension to optical imaging, whic h explains why it is such an excellent instrument for metrological, but also for biological applications. We believe that DHM is, by nature, ideally suited for nonlinear microscopy. In this work, we review the advantages of DHM for nonlinear microscopy and present its application to determination of the axial position of nonlinear nanoparticles capable of second harmonic generation.