Time-domain ptychography, reconstructing temporal objects

Abstract

Ptychography [1], a lens-less imaging technique which reconstructs the spatial phase from measured diffraction patterns, has recently been migrated to the time domain [2]. Time-domain ptychography requires recording several spectral measurements, each with a different relative time delay, of the product of two electrical fields where the one electrical field is seen as a temporal object and the other a temporal probe. Time domain ptychography allows a wide range of temporal objects to be reconstructed with a very versatile range of probe functions. There are at present three reconstruction algorithms which can be used depending on the temporal probe function used. These are variants on the ptychographic iterative engine (PIE) [3]. First we have shown that one can apply ptychography in the time domain by migrating the PIE algorithm to a one dimensional space. For standard time-domain ptychography the requirement is that the probe pulse is known. We then migrated the extended PIE (ePIE) algorithm [4] to the time domain and it was demonstrated with an experiment in the attosecond regime [5]. We also showed that if one has some intrinsic knowledge about the probe, as is the case when the probe is derived from the temporal object by application of a known transfer function, the temporal object can be reconstructed. For this case we developed the intrinsic PIE (iPIE) algorithm [6] and showed that one can use it in order to do pulse characterization.