SELF-INSCRIPTION OF COMPLEX, FUNCTIONAL 3-D STRUCTURES WITH SELF-TRAPPED LIGHT BEAMS

Abstract

The behavior and dynamics of light waves in soft light-responsive polymers were studied. We used the properties of these beams to develop three routes to functional 3-D structures which would be impossible to fabricate through conventional lithography. The method to obtain functional 3-D structures, known as Prismatic 3-D printing, exploits the fact the divergence of beams can be controlled through the rate of photopolymerization which is intensity-dependent, to rapidly 3-D objects. Here, we employ segmentation algorithms to deconstruct a mesh of the desired object into prisms, which are then inscribed in a single step by self-trapped beams to generate a wide range of complex architectures within seconds. Such prisms can be assembled in situ or as a form of post-processing. Each of these prismatic elements has a higher refractive index than their surroundings and they are also continuous along the propagation front direction. These two properties make each prismatic element light-guiding. Taking advantage of this function obtained through our method, remote-controllable waveguide architectures including planar slab waveguide, individual and small arrays of cylindrical waveguides as well as long-range waveguide lattices (>10 000 cm-2) made of electroactive hydrogels were printed using self-trapped beams. By applying and varying external electric fields, we can then dynamically control the bending, angular orientation and rotation (up to 360o) of these pliant light-guiding structures. Reminiscent of the camouflaging techniques of certain marine creatures, this allows precise, remote control of the waveguided light output. Finally, we examined the propagation dynamics and structures inscribed by vortex beams in photopolymerizable systems and showed that they elicited rotation along their propagation paths and ultimately collapsed into self-trapped filaments. The sense of rotation was commensurate with the topological charge of the vortex while the rotation rate was proportional to the intensity of the beam output.