Self-organization of excitations in Ge-doped silica fibers and its role in second harmonic generation
B.P. Antonyuk,
V.B. Antonyuk
Institute of Spectroscopy, Russian Academy of Sciences, ul. Fizicheskaya 5, Troitsk, Moscow, 108840, Russian Federation
Based on Raman and hyper-Raman scattering experiments and on direct green light absorption measurements, excitations of a new type — charge transfer excitons — are found to exist in Ge-doped silica fibers, whose self-organization (orientation ordering of dipole moments) leads to positive feedback in response to a static electric field. An electric field of 105 V/cm then results breaking the inversion symmetry of the initially centrally symmetric medium and allowing the second harmonic to be generated. Generation persists only at the medium preparation stage and self-switches off upon a transition to the stationary state.
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