Multiplexing of volume-dispersing optics by additive manufacturing

3-dimensional pixel distributions (voxels) in transparent material produced by modern production processes can generate targeted different light distributions via optical scattering effects, depending on the incident illumination color and angle. Such elements are highly interesting for a variety of applications.  They have been demonstrated via laser-induced micro-damage in glass bodies, but as a result they are inflexible and require processing downstream steps for practical use.  With current additive manufacturing techniques such as laser direct writing using two-photon polymerization, it would be conceivable to additively manufacture similar structures in an extremely small volume of around 150 x 150 x 150 µm³, which is roughly equivalent to a medium-sized grain of sand. This would enable fabrication even on more complex objects, such as the end of optical fibers, and open up various, flexible areas of application. However, multifunctional, switchable elements in head-mounted displays, augmented reality applications, or controllable light distribution in sensors for minimally invasive medical technology would also be conceivable (funded by the University of Stuttgart and the MWK).