Date/Time
Date(s) - 30/09/2021
1:30 pm - 2:30 pm

Title: Self-inscription of complex, functional 3-Dstructures with self-trapped light fields

 Date: Thursday, September 30, 2021

 Time: 1:30-2:30 pm

Zoom – contact chemgrad@mcmaster.ca for link 

Host: Dr. Kalai Saravanamuttu 

Abstract: Our group studies unusual (nonlinear) forms of light waves andtheir behaviours and dynamics in soft light­ responsive polymers. In this talk,I will describe how we harnessed these properties to develop three routes tofunctional 3-D structures, which would be impossible to fabricatethrough conventional photolithography: (i) Prismatic 3­D printing exploits the divergence-freepropagation of self-trapped beams coupled with their enhanced intensities torapidly print 3-D objects. Here, we employ segmentation algorithms todeconstruct a mesh of the desired object into prisms, which are then inscribedin a single step by self-trapped beams to generate a wide range of complex architectureswithin seconds. (ii) Dynamic, remote-controllable waveguide architecturesincluding planar slab waveguides, individual and small arrays ofcylindrical waveguides as well as long-range waveguide lattices (> 10 000 cm^-2)can be induced by self-trappedbeams in electroactive hydrogels. By applying and varying externalelectric fields, we can then dynamically control the bending, angularorientation and rotation (up to 360°) of these pliant light-guiding structures.Reminiscent of the camouflaging techniques of certain marine creatures, thisallows precise, remote control of the waveguided light output. (iii) Weexamined the propagation dynamics and structures inscribed by vortex beamsin photopolymerizable systems, and showed that they elicited rotation alongtheir propagation paths and ultimately collapsed into self-trapped filaments.The sense of rotation was commensurate with the topological charge of thevortex.