MULTI-PHOTON POLYMERIZATION OF WAVEGUIDE STRUCTURES WITHIN 3D-PHOTONIC CRYSTALS

Wonmok Lee 

Postdoctoral Research Associate, Advanced Chemical Systems Group, Beckman Institute, UIUC

10/4/2001

3rd Floor tower, 3269 Beckman 

Three-dimensional (3D) photonic bandgap (PBG) materials have recently generated great interest for their potential for photonic applications.  3D PBG structures have been postulated as the basis of low-loss waveguides, optical cavities, zero-threshold microlasers, etc. It is believed, for example, that PBG-based waveguides containing bends of radii only several times the wavelength of the propagating light will have very low losses. However, fabrication of PBG-based waveguides and optical cavities will require incorporation of line and point defects, respectively, within 3D PBG structures.  Although layer-by-layer lithographic techniques allow precise control over defect fabrication, they are tedious, expensive, and limited to structures consisting of a finite number of layers. A facile route to 3D periodic structures is colloidal self-assembly. Here we demonstrate the use of a laser scanning confocal microscope (LSCM) for multi-photon polymerization of high resolution 3D patterns in the interior of colloidal crystals.  Multi-photon polymerization is unique in its ability to fabricate intricate submicron 3D features because of the nonlinear sensitivity of the photoinitiation step to photon flux.  We examined various multi-photon polymerization systems, some of which appear to have great promise for defined defect fabrication within self-assembled photonic crystals for the development of PBG-based devices.