Third harmonic generation (THG) provides a valuable, label-free
approach to imaging biological systems. To date, THG microscopy has
been performed using point-scanning methods that rely on intensity
measurements lacking phase information of the complex field. We report
the first demonstration, to the best of our knowledge, of THG
holographic microscopy and the reconstruction of the complex THG
signal field with spatial synthetic aperture imaging. Phase
distortions arising from measurement-to-measurement fluctuations and
imaging components cause optical aberrations in the reconstructed THG
field. We have developed an aberration-correction algorithm that
estimates and corrects these phase distortions to reconstruct the
spatial synthetic aperture THG field without optical aberrations.