Third-order Optical Nonlinearities of Sol-gel Silica Coating Films Containing Metal Porphyrin Derivatives Measured by Resonant Femtosecond Degenerate Four-wave Mixing Technique

摘要

Third-order optical nonlinearities of sol-gel silica coating films containing metal porphyrin derivatives were measured under resonant conditions by the femtosecond degenerate four-wave mixing (DFWM) technique. Temporal profiles of the DFWM signal were measured with a time resolution of 0.3 ps, and were found to consist of two components, the coherent instantaneous nonlinear response and the delayed response with a decay time constant of several to several hundred ps. The latter can be attributed to population grating of an excited state, and contribution, of slow component was very little for a zinc porphyrin derivative. The values of electronic component of the optical nonlinear susceptibility, χ_(xxxx)~((3)) for these films were ca. 2 x 10~(-10) esu.