Advances in Two-Photon Photoinitiators and 3D Microfabrication

Mu!ti-photon three-dimensional micro- and nanofabrication (3DM) is a powerful technique for creating complex 3D microscale structures of the type needed for micro-electromechanical systems (MEMS), micro-optics, and microfluidics. In 3DM high peak-power laser pulses are tightly focused into a medium which undergoes a physical or chemical change following multi-photon (typically two-photon) excitation at the focal point. Complex structures are generated by serial 3D-patterned exposure within the material volume. Application of this technique, beyond laboratory curiosity, has been seriously thwarted by the dearth of photoinitiators that possess both high two-photon absorptivity (2PA) and high polymerization initiation efficiency. The development of new, high efficiency two-photon photoinitiators for 3DM is described as are advances in 3DM in our laboratories;