Abbreviated Journal Title
DOPED POLYMER SYSTEMS; OPTICAL SUSCEPTIBILITY; PERTURBATION THEORY; ORGANIC-MOLECULES; STATES; SQUARAINES; MECHANISMS; MODEL; Optics
The exact formula is derived from the "sum over states" (SOS) quantum mechanical model for the frequency dispersion of the nonlinear refractive index coefficient n(2) for centrosymmetric molecules in the off-resonance and non-resonant regimes. This expression is characterized by interference between terms from two-photon transitions from the ground state to the even-symmetry excited states and one-photon transitions between the ground state and odd-symmetry excited states. When contributions from the two-photon terms exceed those from the one-photon terms, the non-resonant intensity-dependent refractive index n(2) > 0, and vice versa. Examples of the frequency dispersion for the three-level SOS model are given. Comparison is made with other existing theories.
Stegeman, George; Kuzyk, Mark G.; Papazoglou, Dimitris G.; and Tzortzakis, Stelios, "Off-resonance and non-resonant dispersion of Kerr nonlinearity for symmetric molecules Invited" (2011). Faculty Bibliography 2010s. 1946.