Single-Shot Ptychography as a Diagnostic Imaging Technique for Studying Electro-Static Discharge

Recent advances in computational imaging are paving the path towards next generation plasma

imaging technologies. Phase sensitive techniques such as Schlieren imaging, holography and

interferometry are widely used to study the refractive index change caused from plasma breakdown

events, however they are either not directly quantitative in phase, require an external reference, or

require a weakly scattering plasma. Ptychography, a particularly robust computational imaging

technique, offers an alternative quantitative phase imaging technique which does not use an

external reference. Ptychography works by illuminating an object with a finitely supported,

coherent optical probe at overlapping scan positions, and collecting the diffracted intensities on a

camera. Sophisticated algorithms process the data and reconstruct complex images of the object

and probe illumination. Typically, this is achieved by scanning the object relative to the probe

which precludes it from studying transient phenomena. Single-Shot Ptychography (SSP)

overcomes this by using a diffractive optical element to split the input illumination into multiple

orders. The orders cross on the object and diffraction intensities from each order are collected in a

single camera exposure. Here we investigate Single-Shot Ptychography as a next-generation

plasma diagnostic tool. We experimentally demonstrate SSP as a plasma diagnostic tool by

imaging an electro-static discharge event simultaneously in both phase and amplitude. LANL Publication ID: LA-UR-21-25745