Laser-induced vaporization of a stretching sheet of liquid tin

We experimentally study the mass distribution of a sheet of liquid tin formed by the impact of a ns-laser pulse on a spherical microdroplet.The mass distribution is obtained using a low-intensity, second ns-laser pulse, which induces vaporization of the stretching thin tin sheet.This careful vaporization enables the investigation of the thickness profile of the sheet, and its mass, at early times after laser pulse impacton a droplet, which have remained inaccessible by the methods used in recent work [B. Liuet al., Phys. Rev. Appl.13, 024035 (2020)]. Thevaporization method, moreover, allows the visualization of the thick rim that bounds the thin sheet. Our results unambiguously demonstratethat increasing the energy of the ns-laser pulse incident on the droplet, which enables reaching a predetermined target radius more quickly,results in a larger mass fraction remaining in the sheet. Specifically, our studies show a doubling of the sheet mass fraction by reducing therequired expansion time. As a corollary, less tin will end up in other channels of the mass distribution, such as fragments surrounding thesheet. Accordingly, more mass would be available in the target sheet for interaction with the more energetic, main laser pulse that is used inthe industry to produce a hot and dense plasma from tin sheet targets in order to create extreme ultraviolet light for nanolithography.

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