Abstract

Time delayed four-wave-mixing with incoherent light was used to study optical superposition state relaxation in sharp cut color filters (Coming CS2-58 and CS2-59) at room temperature and in Nile Blue in ethanol at 4.5 K. Laser light a 6240 A with a 400 A bandwidth and nsec duration was split and directed to an interferometric setup which introduced a controlled delay between the two split components. The two pulses (components) with wave vectors K₁ and K₂ were recombined in the sample. The resulting induced emissions along the phase matched relative pulse delay. In the color filters, the traces became gradually asymmetric about zero delay as the optical density (thickness) of the samples was increased. This asymmetric character is due to inhomogeneous broadening. We understand this chagne to be due to a modification of the spectral range of the excitation. The traces indicate T₂ is approximately 30 fs. For the Nile Blue dye in ethanol glass, we find that the S0-S1 transition is inhomogeneously broadened with a T_x of approximately 10 fs.

© 1990 Optical Society of America