Variations in the magneto-optic coupling coefficient in a bismuth-lutetium-iron-garnet film

Magnetostatic wave-optical interactions are studied in the transverse geometry using a [BiLu]/sub 3/Fe/sub 5/O/sub 12/ film. Non-monotonic variations in the magneto-optic coupling coefficient are observed as we increase the input microwave power at a fixed frequency. Similar variations are also seen in the transmitted microwave signal, though the features appear at higher power levels. The non-monotonic behavior is due to a shift in the microwave passband with increasing power. Density plots are used to correlate the two sets of data over a 350 MHz region. The discrepancy in power levels associated with a feature in the line plots is a consequence of the different curvatures of the two density plots.