Order-disorder transitions in Langmuir-Blodgett films. III. Polarized Raman studies of cadmium arachidate using integrated optical techniques

Abstract

Polarized Raman measurements of Langmuir-Blodgett (LB) multilayers of cadmium arachidate (CdA) have been obtained through the application of integrated optical techniques. Excitation of either the transverse electric (TE) or transverse magnetic (TM) mode of an asymmetric slab waveguide was alternately used to produce Raman scattering in the CdA multilayers deposited on its surface. Analysis of the 90° scattered light with a polarizer placed at two mutually perpendicular positions for both the TE and TM modes of the waveguide produced a set of four measurements which were used to determine the orientation and lateral order of the CdA monolayer components. The extent of order in the LB film was then investigated as a function of temperature and compared with that of bulk CdA. The temperature of the order-disorder transition was found to be similar in both cases and consistent with that found previously from infrared studies. © 1987 American Institute of Physics.