Label-free second-harmonic phase imaging of biological specimen by digital holographic microscopy.

We have previously developed a new way for nonscanning second-harmonic generation (SHG) microscopy [Opt. Lett. 34, 2450 (2009)]. Based on digital holography, this technique captures, in single-shot hologram acquisition, both the amplitude and the phase of a coherent SHG radiation, which makes possible second harmonic phase microscopy. In this work, we present holographic SHG phase microscopy of a label-free biological tissue and discuss its added value to SHG microscopy.