Enhancement of modulation rate of magneto-optical spatial light modulators with magnetophotonic crystals

摘要

Thin-film-type magneto-optical spatial light modulator has been developed by combining one-dimensional magnetophotonic crystal (MPC) and micropatterned drive lines. The use of MPC is expected to be effective because the apparent Faraday effect, which is directly proportional to pixel contrast, is largely enhanced by the light localization of light in the vicinity of the magnetic defect in magnetophotonic crystal. The magnetophotonic crystal had a multilayer structure of (Ta_2O_5/SiO_2)~k/Bi: yttrium iron garnet/(SiO_2/Ta_2O_5)~k formed on a glass substrate, where k is the repetition number and one of optimization parameters in this study. The transmittance T decreased with an increase of k, while Faraday rotation θ_F increased, indicating that the enhancement of light modulation rate would be achieved by optimizing the figure of merit F denned by F ≈ T sin 2θ_F. At k=6, the maximum F=8.8 was obtained, which is about 20 times larger than that of single layer structure.