Abstract

Irradiation of materials in close proximity to phase masks is currently of interest for fabricating micron-scale Bragg gratings in optical fibres and on planar optoelectronic components. Photo-sensitive silica fibres have been irradiated through a phase mask with a KrF excimer laser to form gratings by single and multiple pulses. We have recently used a silica phase mask with a suppressed zero order (<5%) and a period d = 533 nm to form sub-micron gratings on KrF excimer laser ablated polymers.³ Polymer films (Polyethylene Terephthalate and Polyimide) positioned within 300 µm of the mask were exposed at an average fluence of 25 mJ/cm² for 1-5 pulses to form high- aspect ratio grating structures. Scanning electron microscope examination revealed two dominant microstructures having periods of 533 nm (Fig. 1) and 266 nm on the exposed surface.

© 1994 IEEE