We report very large photoinduced refractive-index changes Δn, of the order of ~10<sup>2</sup>, in lead germanate glass waveguides grown by pulsed-laser deposition. The magnitude of Δn was derived from measurements of diffraction efficiency for gratings written by exposure to 244-nm light through a phase mask, whereas the sign of Δn was determined from ellipsometric data. Results are shown for films grown under oxygen pressures ranging from 1 χ 10<sup>-2</sup> to 6 χ 10<sup>-2</sup>mbars (1.33mbars=1 Torr).
© 1998 Optical Society of America
(050.2770) Diffraction and gratings : Gratings
(160.4670) Materials : Optical materials
(160.4760) Materials : Optical properties
(310.2790) Thin films : Guided waves
(310.6860) Thin films : Thin films, optical properties
Sakellaris Mailis, Andrew A. Anderson, Stephen J. Barrington, William S. Brocklesby, Robert Greef, Harvey N. Rutt, Robert W. Eason, Nikolaos A. Vainos, and Christos Grivas, "Photosensitivity of lead germanate glass waveguides grown by pulsed laser deposition," Opt. Lett. 23, 1751-1753 (1998)