Submicron surface-relief gratings were fabricated in ultrathin dielectric films by F2-laser ablation. Projection mask imaging by a Schwarzschild objective applying nanosecond duration pulses from a high-resolution 157-nm optical processing system generated 780-nm-period gratings in various thin oxide layers. The grating modulation depths were controlled within tens of nanometers by applying suitable energy densities and number of pulses. Thus, high-resolution laser ablation proves to be a promising alternative approach to well-known lithographic methods for the fabrication of submicron-period gratings in thin films. Such gratings are the most critical component of grating waveguide structures (GWS) that comprise of a substrate, a thin waveguide, and a grating layer in a planar multilayer structure. Interference effects in a GWS will provide high reflection efficiency under resonance conditions for an ideal grating with no absorption losses. The resonance spectral responses of the F2-laser ablated gratings have been investigated using an ultrashort-pulse titanium-sapphire laser. Their potential for optical applications will be shown and discussed. GWS are attractive for optical switches or modulators, narrow-band spectral filters, high reflectivity mirrors, bio-sensor chips and many other applications.

Date Published: 9 December 2004
PDF: 9 pages
Proc. SPIE 5578, Photonics North 2004: Photonic Applications in Astronomy, Biomedicine, Imaging, Materials Processing, and Education, (9 December 2004); doi: 10.1117/12.567350

Published in SPIE Proceedings Vol. 5578:
Photonics North 2004: Photonic Applications in Astronomy, Biomedicine, Imaging, Materials Processing, and Education
Marc Nantel; Glen Herriot; Graham H. McKinnon; Leonard MacEachern; Robert A. Weersink; Rejean Munger; Andrew Ridsdale, Editor(s)