A phenomenon of a strong irreversible variation of the refractive index (Δn approximately equals - 0.2) in a subsurface layer of the lithium niobate crystal has been observed. The effect arises under the strong absorption of high-power radiation with wavelength 248 nm of KrF excimer laser. The characteristics of the subsurface photorefractive effect (SPRE) were identified by using the data on measurements of the reflection coefficient of a crystal and of the diffraction efficiency of a recorded phase grating. About 40% of niobium and oxygen atoms has been found to be displaced from the lattice points in the 350 ± 50 angstrom subsurface layer. This phenomenon was used for creation of some integrated optics elements.

Date Published: 17 October 2003
PDF: 7 pages
Proc. SPIE 4977, Photon Processing in Microelectronics and Photonics II, (17 October 2003); doi: 10.1117/12.479248

Published in SPIE Proceedings Vol. 4977:
Photon Processing in Microelectronics and Photonics II
Alberto Piqué; David B. Geohegan; Friedrich G. Bachmann; Koji Sugioka; Frank Träger; Jan J. Dubowski; Peter R. Herman; Willem Hoving; Kouichi Murakami; Kunihiko Washio; Jim Fieret, Editor(s)