Open AccessExcited-state enhancement of third-order optical nonlinearities: photodynamics and characterization
Author(s) -
Bing Gu,
Kai Lou,
Jing Chen,
Yongnan Li,
HuiTian Wang,
Wei Ji
Publication year - 2010
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.18.026843
Subject(s) - excited state , picosecond , femtosecond , nanosecond , nonlinear system , nonlinear optics , optics , physics , refraction , absorption (acoustics) , laser , quantum mechanics
Based on the simplified five-level rate-equation theory, we investigate the hybrid third-order optical nonlinear processes which combine the instantaneous nonlinearity and the one-photon absorption induced excited-state nonlinearity. We obtain the analytical third-order nonlinear absorption and refraction coefficients originating from the singlet and triplet excited-state effects. We explore the photodynamic process and give the corresponding level diagram in the nanosecond, picosecond, and femtosecond regimes. We develop the pulse-duration-dependent Z-scan theory for characterizing the simultaneous instantaneous nonlinearity and cumulative effect of the excited-state nonlinearity. We also demonstrate the validity of the presented theory to analyze the experimental results.