High-resolution F2-laser machining of micro-optic components

The F-2-laser Nanofabrication Facility at the University of Toronto delivers high-fluence 157-nm radiation at high resolution to microfabricate high-finesse silica-based optical components. The 7.9-eV photons drive strong material interactions near the band-edge states of fused silica and related glasses that help avoid microcrack formation, a common limitation of longer wavelength lasers. The strong interactions provide for small and smooth excisions, offering depth control on a scale of tens of nanometers. A 157-nm beam homogenization system and a 25x Schwarzschild lens provided a uniform (+/-5%) on-target fluence of 9 J/cm(2) in a 0.25 mm x 0.25 mm field. Larger work area was enabled by synchronously driving the projection mask and target motion stages. The 0.4 NA lens supported the formation of high-aspect channel walls and surface-relief features as small as similar to500 nm. Both mask projection and direct writing technique were employed. The novel aspects of the optical beam delivery system are presented together with results on fabricating microchannels, cutting optical fiber, fabricating surface relief grating and cylindrical lens. The results demonstrate broad application directions for fabricating telecommunication devices, general optical and photonic components, and biological devices.