  Efficient coupling of intense laser pulses to solid-density matter is
critical to many applications including ion acceleration for cancer therapy. At
relativistic intensities, the focus has been mainly on investigating various
laser beams irradiating initially flat interfaces with little or no control
over the interaction. Here, we propose a novel approach that leverages recent
advancements in 3D direct laser writing (DLW) of materials and high contrast
lasers to manipulate the laser-matter interactions on the micro-scales. We
demonstrate, via simulations, that usable intensities >10^23Wcm^(-2) could be
achieved with current tabletop lasers coupled to 3D printed plasma lenses. We
show that these plasma optical elements act not only as a lens to focus laser
light, but also as an electromagnetic guide for secondary particle beams. These
results open new paths to engineering light-matter interactions at
ultra-relativistic intensities.
