  Ptychography is an attractive advance of coherent diffraction imaging (CDI),
which can provide high lateral resolution and wide field of view. The
theoretical resolution of ptychography is dose-limited, therefore making
ptychography workable with a broadband source will be highly beneficial.
However, broad spectra of light source conflict with the high coherence
assumption in CDI that the current reconstruction algorithm were built upon. In
this paper, we demonstrated that incorporation of a blind deconvolution in the
reconstruction algorithm can improve the image quality of ptychography with
broadband source. This broadband reconstruction algorithm can obtain
high-quality amplitude and phase images of complex-valued samples requiring no
knowledge of the illumination spectrum. Optical experiments using biological
samples demonstrate the effectiveness of our method. The significant
improvement in low coherence tolerance by our approach can pave the way for
implementing ultrafast imaging with femtosecond or attosecond lasers or
high-flux ptychographic imaging with laboratory EUV or X-ray sources.
