Single-shot imaging of surface molecular ionization in nanosystems

Fenghao Sun,Botao Wu,Fei Chen,Hui Li,Qiwen Qu,Chenxu Lu,Hongxing Xu,Shanshan Song,Hongcheng Ni,Jiawei Wang,Jian Wu

doi:10.1515/nanoph-2021-0172

Fenghao Sun, Botao Wu + Show 9 more

Open Access

https://doi.org/10.1515/nanoph-2021-0172

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Journal: Nanophotonics	Publication Date: Jul 12, 2021
Citations: 8	License type: CC BY 4.0

Affiliation: East China Normal University, Shanxi University

Abstract

Abstract Using single-shot velocity map imaging technique, explosion imaging of different ion species ejected from 50 nm SiO2 nanoparticles are obtained excitedly by strong near-infrared and ultraviolet femtosecond laser fields. Characteristic momentum distributions showing forward emission of the ions at low excitation intensities and shock wave behaviors at high intensities are observed. When the excitation intensity is close to the dissociative ionization threshold of the surface molecules, the resulting ion products can be used to image the instant near-field distributions. The underlying dynamics of shock formation are simulated by using a Coulomb explosion model. Our results allow one to distinguish the ultrafast strong-field response of various molecular species in nanosystems and will open a new way for further exploration of the underlying dynamics of laser-and-nanoparticle interactions.

Highlights

Interactions between nanosystems and light fields play crucial roles in the development of laser machining [1,2,3], cancer treatment [4, 5], photocatalysis [6], etc
The generated ions in the interactions of femtosecond laser pulses with the nanoparticle systems were guided toward a microchannel plate (MCP)/phosphor detector at the end of the spectrometer and the induced images were detected by a high-speed single-shot camera (Phantom V410)
time of flight (TOF) measurements showed dominating H+ and Si+ ion products in the ion emissions, where the H+ ions can be generated from the surface molecules while the Si+ ions are from the ionization of SiO2 nanoparticles

Summary

Introduction

Interactions between nanosystems and light fields play crucial roles in the development of laser machining [1,2,3], cancer treatment [4, 5], photocatalysis [6], etc. When excited with femtosecond laser fields, near field enhancement can be induced around the nanostructures that changes dramatically in femtosecond time scales. Aerosol nanoparticle sources in vacuum systems have been implemented to explore their interactions with femtosecond laser pulses [7,8,9,10]. The generated charged fragmentation can be detected by velocity map imaging (VMI) [7,8,9,10], time of flight (TOF) spectroscopy [11,12,13], and even reaction microscopy [14, 15]. The reaction nanoscope shows impressive potential for exploring nanoparticle dynamics, by performing coincidence measurements on the ions generated from nanoparticles [14]

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