Construction of defect-diminished fatty acid Langmuir-Blodgett film and its optical waveguide properties

A Langmuir-Blodgett (LB) film for a optical planar waveguide with a low optical propagation loss could be constructed from highly organized fatty acid monolayers prepared by a cooling multi-step creep method. The cooling multi-step creep method is the novel preparation technique to form a defect- diminished monolayer on the water surfaces on the basis of both the structural relaxation induced by area-creep and the control of thermal molecular motions in the monolayer. The fatty acid monolayer prepared by the cooling multi-step creep method was morphologically homogeneous and mechanically stable, even at a high surface pressure where the monolayer prepared by a conventional continuous compression method easily collapsed. The crystallographical and structural regularities of the monolayer and the LB film prepared by the cooling multi-step creep method were remarkably improved, compared with those of the monolayer and the LB film prepared by the conventional continuous compression method. The LB film waveguides prepared by the cooling multi-step creep method were morphologically homogeneous and structurally regular and could propagate incident light with a low optical propagation loss.