Wmkp. Wijekoon et al., 2ND-HARMONIC GENERATION IN MULTILAYER LANGMUIR-BLODGETT-FILMS OF BLUETRANSPARENT ORGANIC POLYMERS, Journal of the American Chemical Society, 118(18), 1996, pp. 4480-4483
Multilayer Langmuir-Blodgett (LB) films were fabricated with two blue
transparent nonlinear optical polymers in which the orientation of the
nonlinear optical chromophore in one polymer is reversed with respect
to the other. The intensity of the frequency-doubled light generated
in these multilayers increases quadratically, with the increasing numb
er of bilayers indicating that the macroscopic optical nonlinearity, c
hi((2)), of the bilayer is a linear sum of the macroscopic optical non
linearities of the individual monolayer. Also, multilayer LB films of
each blue transparent polymer were made by alternate deposition with a
spacer polymer, poly(tert-butyl methacrylate). The intensity of the f
requency-doubled light generated by these multilayer films was approxi
mately 4 times smaller than that generated by multilayer films of two
blue transparent polymers with the same number of layers, indicating t
hat the use of another nonlinear optical active polymer in the place o
f passive poly(tert-butyl methacrylate) polymer leads to considerable
improvement in the frequency-doubling efficiency. Multilayer LB films
of these polymers show a great potential for achieving a practical lev
el of performance.