Clear observation of the formation of nanoparticles inside the ablation bubble through a laser-induced flat transparent window by laser scattering

Abstract

We demonstrate the clear observation of laser-scattering signals from Ag nanoparticles (NPs) inside an ablation bubble.

Design and perspective of amorphous metal nanoparticles from laser synthesis and processing

“…The clear observation of NPs inside the cavitation bubbles has also been reported by the ablation through a thin Ag film deposited on a transparent glass substrate, where this novel setup suppressed the light scattering from bubble surface and easily obtained scattering signals by the simple inverse light scattering analysis. 141 The reactive speics (atoms or atomic clusters) during the laser ablation of Zn target was also detected by NEXAFS in the vapor bubbles, as shown by Reich et al 142 It has been known that the formation of laser-induced plasma in LAL is a far from equilibrium process and thus the vapor condensation also proceeds in nonequilibrium conditions. 70,74,143 In particular ultrashort-pulsed LAL usually provides a large temperature gradient at an initial cooling rate of 10 12 -10 13 K/s when metal droplets are jetted into a colder and high-density liquid environment, 59 facilitating the formation of metastable and defect-rich structures.…”

Ultrashort pulse laser ablation in liquids: probing the first nanoseconds of underwater phase explosion

“…Imaging of the cavitation bubbles, usually performed with time-resolved shadowgraphy 5 , 6 , combined with laser-scattering 7 , or X-ray probing 8 , 9 of the interior of the cavitation bubbles, has provided valuable information on the expansion and collapse of the cavitation bubbles, as well as the evolution of the size and crystallinity of the nanoparticles. The initial stage of the ablation process at the origin of the emergence of the cavitation bubble and the nanoparticles, however, has largely remained beyond reach for in situ experimental probing.…”

In situ speciation and spatial mapping of Zn products during pulsed laser ablation in liquids (PLAL) by combined synchrotron methods

“…The observation of the macroscopic dynamics is directly accessible in visible-light PLAL investigations. A large setback is the difficult access to the bubble interior 35 as well as the low sensitivity on nanoparticle distribution. Dense clouds of nanoparticles are readily seen, however, a disambiguation from permanent-gas microbubbles is difficult.…”

“…18 Standard laboratory approaches to capture dynamics in this early time scale have been limited to high-speed videography 29,30 or light ( plasma) emission or scattering. [31][32][33][34][35] Snapshot imaging with visible light has been used extensively to visualize the formation of a cavitation bubble after the intense heating of the target-liquid interface. High-speed cameras are combined with shadowgraphy to film the bubble on a microsecond time scale.…”

“…17 Optical spectroscopy 12 is virtually impossible to apply before the bubble has vanished due to the strong perturbation by refraction and opaque micro bubble clouds. Novel approaches via creation of a laserinduced flat transparent window allow the clear observation of the formation of nanoparticles inside the ablation bubble through laser scattering, 35 but without chemical speciation or exact size determination. Thus, particle sensitivity and quantification of ablated mass yield is difficult to obtain in situ.…”