Isotropic contractive scaling of laser written microstructures in vitrified aerogels

A novel route is presented enabling minimization of feature sizes via laser ablative micro-patterning in highly porous silica aerogel monoliths and subsequent viscous sintering. Vitrification yields isotropically contracted silica solids preserving their original stereometric forms. The contraction depends on aerogel structure and porosity and we demonstrate here the first realization of a 3:1 ratio. Surface relief and void micropatterns inscribed in the monolith also undergo isotropic contraction and feature minimization beyond the spatial resolution of their original recording. Experimental results provide clear evidence that embedded void structures undergo contraction larger than the nominal stereometric scaling. This is a demonstration of a generic principle that enables fundamental physical resolution limits to be surpassed, leading to new avenues in micro- and nano-fabrication technologies.