Experimental time-resolved imaging by multiplexed ptychography.

Omri Wengrowicz,U Satya Sainadh,Barry Loevsky,Gil Ilan Haham,Bing Kuan Chen,Or Peleg,Oren Cohen

doi:10.1364/oe.27.024568

Abstract

A recently proposed technique introduced a time-resolved option of fast transient non-repetitive events to ptychographic microscopy. This technique, termed time-resolved imaging by multiplexed ptychography (TIMP), is based on algorithmic reconstruction of multiple frames from data recorded in a single camera acquisition of a single-shot ptychographic microscope. We demonstrate TIMP experimentally, reconstructing thirty-six frames of a dynamical complex-valued object from ptychographic data recorded in a single camera snapshot.

Highlights

Ptychography [1] is a powerful coherent diffractive imaging (CDI) [2] technique, yielding a labelfree, high-contrast quantitative amplitude and phase information, which does not require prior information on the object and the probe beam
We use two different encoding approaches to acquire mutually orthogonal pulses – an orbital angular momentum encoding (OAME) which is based on the orthogonality of Laguerre-Gaussian beams [16], and a phase gradient encoding (PGE) which shifts transversely the pattern induced by the micro-lens array (MLA)
Time-resolved imaging by multiplexed ptychography (TIMP) is a new scheme for multi-frame imaging from data recorded in a single camera snapshot [7]

Summary

Introduction

Ptychography [1] is a powerful coherent diffractive imaging (CDI) [2] technique, yielding a labelfree, high-contrast quantitative amplitude and phase information, which does not require prior information (e.g. support) on the object and the probe beam. In a conventional ptychographic microscope, a complex-valued object is scanned in a stepwise fashion through a localized beam. The far-field intensity diffraction pattern from the illuminated region on the object is recorded. A limitation of conventional ptychography is the long acquisition time (> 1ms) due to the scanning, precluding the application of ptychography to imaging of fast dynamics. To overcome this restriction, single-shot ptychography (SSP) schemes, in which ptychographic data (multiple intensity diffraction patterns from overlapping regions) is recorded in a single camera exposure, were proposed and demonstrated [5,6,7,8,9]. Ultrafast SSP (single frame of a static object) was demonstrated using a single 150 psec pulse illumination [7]

Methods

Results

Conclusion