Plasma channel formation in NIR laser-irradiated carrier gas from an aerosol nanoparticle injector

Abstract

Aerosol nanoparticle injectors are fundamentally important for experiments where container-free sample handling is needed to study isolated nanoparticles. The injector consists of a nebuliser, a differential pumping unit, and an aerodynamic lens to create and deliver a focused particle beam to the interaction point inside a vacuum chamber. The tightest focus of the particle beam is close to the injector tip. The density of the focusing carrier gas is high at this point. We show here how this gas interacts with a near infrared laser pulse (800 nm wavelength, 120 fs pulse duration) at intensities approaching 10 16 Wcm −2 . We observe acceleration of gas ions to kinetic energies of 100s eV and study their energies as a function of the carrier gas density. Our results indicate that field ionisation by the intense near-infrared laser pulse opens up a plasma channel behind the laser pulse. The observations can be understood in terms of a Coulomb explosion of the created underdense plasma channel. The results can be used to estimate gas background in experiments with the injector and they open up opportunities for a new class of studies on electron and ion dynamics in nanoparticles surrounded by a low-density gas.

A multipurpose end-station for atomic, molecular and optical sciences and coherent diffractive imaging at ELI beamlines

“…The injector, either with GDVN or ES, can be installed on the top DN250CF port of the MAC chamber on an xyz manipulator. When the injector is in operation, the vacuum level in MAC chamber rises typically to 10 −6 − 10 −5 mbar, still allowing ion or electron spectroscopy [70] (Sect. 4.1, Fig.…”

“…In the first commissioning experiments, the gas background from the nanoparticle injector has been thoroughly characterized by the determination of energies of ions created in the interaction with a strong NIR laser field. It has been shown that a plasma channel can be created in the interaction volume and the measured ion energies can be used to estimate the gas density [70].…”

A Multipurpose End-Station for Atomic, Molecular and Optical Sciences and Coherent Diffractive Imaging at ELI Beamlines

“…The injector, either with GDVN or ES, can be installed on the top DN250CF port of the MAC chamber on an xyz manipulator. When the injector is in operation, the vacuum level in MAC chamber rises typically to 10 −6 − 10 −5 mbar, still allowing ion or electron spectroscopy [70] (section IV A, Fig. 10(b)).…”

Focused particle streams for electron emission studies from intense laser plasma interactions

“…al. [7]. Mesoscopic particles dispersed as an effusive jet in a vacuum have been shown to generate hard X-rays with energies up to 100 keV [5].…”

“…Although the collimated beam of nanoparticles by ALS has been studied for ion generation, time-of-flight studies [7] and single particle diffractive imaging [9], their application in high-energy electron generation using laser-plasma interaction remains unexplored. With the growing interest in microtargets for relativistic and nearrelativistic electron production [5,6,20,21], the use of an ALS provides a platform for studying and understanding the physics of laser-plasma interactions in mass-isolated structured targets.…”