Influences of Focusing Conditions on Dynamics of Laser Ablation at a Solid–Liquid Interface

Abstract

Influences of focusing conditions relative to a sample surface on shock processes in under-liquid laser-induced ablation were studied using a custom-designed time-resolved photoelasticity imaging technique. A nanosecond laser pulse was focused onto the surface of epoxy-resin blocks immersed in liquids. When the surface was located close to the focal point, the breakdown that occurred on the solid–liquid interface resulted in reduced laser-induced stress. At positions above the focal point, the stress-wave intensity was mainly determined by laser pulse energy, but not by fluence. Impurities in liquids initiated breakdowns at multiple sites along the light path and reduced stress-wave intensity.

Bubble dynamics in metal nanoparticle formation by laser ablation in liquid studied through high-speed laser stroboscopic videography

“…When a short, high-powered laser pulse is irradiated onto a solid surface in water, a very high level of stress is induced by the confinement effect of the surrounding water on the plasma. We have directly observed and reported this effect using a high-speed camera and a high-speed video camera [13][14][15]. In order to visualize this process, we have developed a custom-designed high-speed videography system designated "high-speed laser stroboscopic videography".…”

“…The behavior of laser-induced bubbles on a metal plate was studied [19]. Our previous results have revealed various aspects of the dynamic phenomena that occur during laser ablation on solid targets in liquid, as well as inside the solid itself [13][14][15].…”

Target geometry and rigidity determines laser-induced cavitation bubble transport and nanoparticle productivity – a high-speed videography study

“…Previous studies with this technique have resolved several processes occurring during PLAL, in a time resolution of less than 0.1 ns and minimum image intervals of 1000 ns. 12,20,21 In this work, we demonstrate a detailed observation of the bubble dynamics for different target geometries and focus our work on the collapse behaviour of the cavitation bubble, which has a major influence on the NP productivity since the NPs are dispersed into the liquid during this collapse. 8,16 Higher NP productivities were observed for the wire geometry ablation due to an efficient transport of nanoparticles into the liquid caused by a backward impulse of the wire and a subsequent displacement of the cavitation bubble from the wire surface.…”

Fluence Threshold Behaviour on Ablation and Bubble Formation in Pulsed Laser Ablation in Liquids

“…[4,17,21,22] Besides linear absorption of the light in the target, nonlinear processes set in at high powerd ensities. [4,17,21,22] Besides linear absorption of the light in the target, nonlinear processes set in at high powerd ensities.…”

“…PLAL and laser-induced cavitation have been observed for different conditions, such as laser pulse length from femtoseconds to hundreds of nanoseconds or focusingc onditions, including focusing under shallow water columns. [4,17,21,22] Besides linear absorption of the light in the target, nonlinear processes set in at high powerd ensities. Excitation with IR pulses can lead to dielectric breakdown by multiphoton absorption in water and finally plasma ignition.T his has been used to study bubble dynamics in bulk water and close to interfaces.…”