The Applications of Multiphoton Absorption Polymerization

Title of Dissertation:THE APPLICATIONS OF MULTIPHOTONABSORPTION POLYMERIZATION Sijia Qin, Doctor of Philosophy, 2013 Directed By:Professor John T. Fourkas,Department of Chemistry and Biochemistry Among various nano/micro-fabrication techniques, multiphoton absorptionpolymerization (MAP) stands out for its high resolution and its capability of creatingarbitrary three-dimensional micro-structures. This thesis will focus on theapplications of, and improvements to, MAP. MAP was used to fabricate polymer double-ring resonators (DRRs) becauseMAP’s high resolution allows for precise control of the coupling gap sizes. Pedestalacrylic DRRs with 33 nm free spectral range and -15 dB isolation were fabricated,and their properties showed qualitative agreement with simulation results. Single-mode, acrylic microring resonator devices were fabricated on a low-index substrate using MAP and were coupled to side-polished fibers as in-linedevices. High-finesse spectral notches with low insertion loss were observed at the fiber output. Surface mapping of the polished face of the fiber was accomplished bymoving a microring resonator device across and along the fiber core. The optimalcoupling region on the polished face of the fiber could be identified through the change of modulation depth. Spectral modulation induced by varying the pressure ona microring resonator device coupled to a side-polished fiber was also investigated. Efficient multiphoton radical generation chemistry has been developed for usein aqueous media and has been applied to the fabrication, manipulation, and assemblyof 3-D polymeric and biomolecular structures through a combination of MAP andoptical tweezers. The combination of MAP and optical tweezers allows for therealization of structures such as tape-like and rope-like microthreads that can be usedin complex microfabrication techniques such as microbraiding and microweaving.These capabilities enhance the toolbox of methods available for the creation of functional microstructures in aqueous media. MAP-fabricated and UV-cured acrylic patterns were treated with reactive ionetching (RIE) to create high-roughness “nanograsses.” The nanograss patterns haveshown the potential to be used as superhydrophobic materials. The density anddimension of the nanograss depends on the total exposure dose. Different etch anglesgave different etch structures. THE APPLICATIONS OF MULTIPHOTON ABSORPTION POLYMERIZATION