DYNAMIC CONVERSION OF OPTICAL MODES IN MAGNETIC GARNET-FILMS INDUCED BY RESONANCES OF PERIODIC STRIPE DOMAINS

Magnetic garnet films of composition (Y,Bi)(3)(Fe,Al)(5)O-12 are grown by liquid phase epitaxy on [111] oriented substrates of Gd3Ga5O12. Th ey support periodic lattices of parallel stripe domains. A simple stri p antenna is used to excite the domain wall resonance and the two bran ches of the domain resonance in the frequency range up to 5 GHz. The r esonance frequencies and the dynamic components of the magnetization a re calculated using a hybridization model. Good agreement between calc ulated and measured resonance frequencies is obtained if the quality f actor of the film is larger than 0.6. Optical modes are coupled into t he waveguiding film. The excited domain resonances cause dynamic conve rsion of transverse electric and transverse magnetic modes by the Fara day and the Cotton-Mouton effects. Mode coupling and conversion are ca lculated by the perturbation theory. The dynamic conversion efficienci es are measured at the fundamental and the first harmonic frequency an d at zero diffraction order as a function of the static induction appl ied in the film plane parallel to the stripes. Conversion efficiencies up to 18% are achieved at a frequency of 2.8 GHz. From the experiment al data the precession angles are derived.