A new experimental method for observing chromophore relaxation dynamics in nonlinear optical polymer systems is described. The method is similar to dielectric relaxation measurements, which probe the linear susceptibility χ(1), but this new method is chromophore selective and probes the nonlinear susceptibility χ(2) in the frequency domain, monitoring second-harmonic generation during the application of a strong ac electric field. The out-of-phase component of χ(2) exhibits behavior similar to that of the loss component in dielectric relaxation and is shown to be unaffected by electric-field-induced third-order effects. The relation to dielectric relaxation is discussed, and stretched exponential parameters are extracted for a Disperse-Red-1/poly(methyl methacrylate) guest–host system.
© 1998 Optical Society of America
(060.2330) Fiber optics and optical communications : Fiber optics communications
(160.5470) Materials : Polymers
(190.4400) Nonlinear optics : Nonlinear optics, materials
(250.5300) Optoelectronics : Photonic integrated circuits
W. N. Herman and J. A. Cline, "Chielectric relaxation: chromophore dynamics in an azo-dye-doped polymer," J. Opt. Soc. Am. B 15, 351-358 (1998)