Structural origin of the nonlinear optical properties of lead niobium germanate film glasses
- Laser Processing Group, Instituto de Optica (CSIC), Serrano 121, 28006 Madrid (Spain)
- Instituto de Estructura de la Materia (CSIC), Serrano 121, 28006 Madrid (Spain)
The structural origin of the nonlinear optical susceptibility (/{chi}{sup (3)}/) of lead-niobium-germanate film glasses with large Nb{sub 2}O{sub 5} contents has been investigated. /{chi}{sup (3)}/ shows a strong enhancement with the Nb content in the films with /{chi}{sup (3)}/ values close to 2 x 10{sup -11} esu at 800 nm for a Nb content as high as 0.71. Boling-Glass-Owyoung and Lines' semiempirical models predict accurately the values of /{chi}{sup (3)}/ for transparent bulk glasses but not for film glasses. This discrepancy is related to the remarkable structural differences between them. Raman spectroscopy suggests the formation of a three-dimensional (3D) structure of [NbO{sub 6}] octahedra in the case of film glasses having large Nb contents, while X-ray photoelectron spectroscopy shows that a significant fraction of these units contain Nb{sup 4+} ions. The combination of a 3D structure of [NbO{sub 6}] with the presence of Nb{sup 4+} polarons and their migration through electron intervalence transfer is proposed as the origin of the observed enhancement of /{chi}{sup (3)}/ in the film glasses.
- OSTI ID:
- 22038650
- Journal Information:
- Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 2 Vol. 110; ISSN JAPIAU; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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