Ultrafast, Single-Event Ptychographic Imaging of Transient Electron Dynamics

Dynamic phenomena occurring on the ultrafast time scales are inherently difficult to image. While pump–probe techniques have been used for decades, probing nonrepeatable phenomena precludes this form of imaging. Additionally, many ultrafast phenomena, such as electron dynamics, exhibit low amplitude contrast in the optical wavelength range and thus require quantitative phase imaging. To better understand the underlying physics involved in a plethora of ultrafast phenomena, advanced imaging techniques must be developed to observe single events at an ultrafast time scale. Here, we present, to the best of our knowledge, the first ptychographic imaging system capable of observing ultrafast dynamics from a single event. We demonstrate ultrafast dynamic imaging by observing the conduction band electron population from a 2-photon absorption event in ZnSe pumped by a single femtosecond pulse. We verify experimental observations by comparing them to numeric solutions of a nonlinear envelope equation. Our imaging method represents a major step forward in ultrafast imaging, bringing the capabilities of ptychography to the ultrafast regime

Supplementary document for At-Focus Scanning Ptychography for High Resolution Imaging with a Wide Field of View - 6719937.pdf

Supplementary document supporting the main manuscript. The .zip files contains the default Optica Latex template files, main text document, and figures

Supplementary document for At-Focus Scanning Ptychography for High Resolution Imaging with a Wide Field of View - 6719937.pdf

Supplementary document supporting the main manuscript. The .zip files contains the default Optica Latex template files, main text document, and figures

Single-pulse, reference-free, spatiospectral measurement of ultrashort pulse-beams

High-intensity pulse-beams are ubiquitous in scientific investigations and industrial applications ranging from the generation of secondary radiation sources (e.g., high harmonic generation, electrons) to material processing (e.g., micromachining, laser-eye surgery). Crucially, pulse-beams can only be controlled to the degree to which they are characterized, necessitating sophisticated measurement techniques. We present a reference-free, full-field, single-shot spatiospectral measurement technique called broadband single-shot ptychography (BBSSP). BBSSP provides the complex wavefront for each spectral and polarization component in an ultrafast pulse-beam and should be applicable across the electromagnetic spectrum. BBSSP will dramatically improve the application and mitigation of spatiospectral pulse-beam structure

Platinum(II/IV) complexes containing ethylenediamine-N,N '-di-2/3-propionate ester ligands induced caspase-dependent apoptosis in cisplatin-resistant colon cancer cells

Several new R(2)eddp (R = i-Pr, i-Bu; eddp = ethylenediamine-N,N'-di-3-propionate) esters and corresponding platinum(II) and platinum(IV) complexes of the general formula [PtCln(R(2)edda-type)] (n = 2, 4) were synthesized and characterized by spectroscopic methods (IR, H-1 and C-13 NMR) and elemental analysis. The crystal structure of platinum(IV) complex [PtCl4{(c-Pe)(2)eddip}] (3a) was resolved and is given herein. Ligand precursors, platinum(II), and platinum(IV) complexes were tested against eight tumor cell lines (CT26CL25, HTC116, SW620, PC3, LNCaP, U251, A375, and B16). Selectivity in the action of those compounds between tumor and two normal primary cells (fibroblasts and keratinocytes) are discussed. A structure-activity relationship of these compounds is discussed. Furthermore, cell cycle distribution, induction of necrosis, apoptosis, autophagy, anoikis, caspase activation, ROS, and RNS are presented on the cisplatin-resistant colon carcinoma HCT116 cell line