Large deuterium isotope effect in the optical nonlinearity of dye-doped liquid crystals.

Deuterium-hydrogen isotopic substitution was found to approximately double the magnitude of the giant optical nonlinearity of dye-doped nematic liquid crystals arising from photoinduced molecular reorientation. In accordance with the predictions of our model, this doubling is well correlated with the increase in a characteristic decay time of the electronically excited dye anisotropy, as measured with time-resolved fluorescence. A similar isotopic effect is predicted for the optical Kerr nonlinearity of dyed isotropic liquids.