Vector-Magneto-Optical Generalized Ellipsometry applied to magnetically anisotropic multilayer and metamaterial samples

Magneto-optical generalized ellipsometry is the most general approach to characterize the magneto-optical response of magnetically anisotropic materials [1]. We extended this experimental approach to Vector-Magneto-Optical Generalized Ellipsometry (VMOGE) in the IR-UV spectral range, by combining a generalized spectroscopic ellipsometer with a 3D vector magnet [2]. VMOGE measures the upper 3 x 4 submatrix of the 4 x 4 Mueller matrix in a magnetic field of arbitrary orientation and magnitude up to 0.4 T at room temperature. Searching the best match model between experimental and calculated VMOGE data, the complex-valued magneto-optical dielectric tensor is determined. Comparison with vector magnetometry measurements can provide the complex and anisotropic magneto-optical coupling constant Q_x, Q_y, Q_z. We have determined the wavelength dependence of the isotropic Qx and Qy of ferromagnetic Co, Fe, and Ni films. Besides, VMOGE is also employed to study Co nanowires [3] with very strong anisotropic optical response. Having knowledge of the magneto-optical coupling constant Q, one can design magneto-optical devices, e.g., ferromagnetic thin film and nanowire structures, with a strong magneto-optical response for a selected wavelength.

[1] D. Schmidt, T. Hofmann, C.M. Herzinger, E. Schubert, and M. Schubert, Appl. Phys. Lett. 96 (2010) 091906.
[2] K. Mok et al. ‘Vector-Magneto-Optical Generalized Ellipsometry’, Rev. Sci. Instrum., submitted
[3] M. Ranjan et al. ‘Optical properties of silver nanowire arrays with 35 nm periodicity’ Optics Letters 35 (2010) 2576.