Laser cut samples were prepared from cast poly(methyl methacrylate) (PMMA) slabs (thickness = 1.6 mm) doped with Lumogen Red 305 (LR305) at ~100 ppm, which were a kind gift from Prof. Michael Debije (Eindhoven University of Technology). Analogous geometries were printed using a fused deposition modelling (FDM) 3D printer (Prusa MK3S i3), which was chosen for ease of use. Custom LR305-PMMA filament was prepared in-house from a physical mixture of PMMA pellets (Sigma Aldrich, MW = 120 kDa) with LR305 powder (100 ppm, BASF) which was extruded using a screw extruder (Noztek Pro). LSCs were printed using a layer height of 0.05 mm, line width of 0.4 mm, infill of 100%, and concentric printing pattern. Further details of the extrusion and 3D-printing parameters, along with the dimensions and geometric gain of each design are available in the Supporting Information (see Table and). .