Abstract
Waveguide linear-dichroism measurements were used in determining the molecular orientation of N-(sulfopropyl)-4-(p-dioctylaminostyryl) pyridinium in Langmuir–Blodgett monolayers upon 150-μm-thick glass (Ti:Zn) substrates in real time. Acquisition of complete spatial-decay curves in t − 1 s with Plaser = 100 μW was made possible by combining propagation in integrated-optical structures with direct imaging of monolayer or glass fluorescence onto the active area of a charge-coupled device camera. Multichannel detection permitted measurement of optical waveguide loss coefficients and ultimately of molecular orientations in approximately 10−3 of the amount of time required by previous methodology. The effects of sample preparation and materials processing on the accuracy and precision of dichroic ratios are discussed. Observed dichroic ratios for a hemicyanine dye revealed no measurable change in the orientation of the electronic transition-dipole moment when Langmuir–Blodgett films were deposited at different surface pressures. These results are in good agreement with the results from singly resonant second-harmonic generation experiments.
© 1991 Optical Society of America
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