Component-Resolved Determination of the Magnetization by Magnetization-Induced Optical Second Harmonic Generation
Thomas Gerrits, Thomas J. Silva, Hugo A. van den Berg, Theo Rasing
We present a method for simultaneous measuring the two normalized in-plane magnetization components in magnetic thin films that allows for the reconstruction of the magnetization angle and the normalized value of the magnetization with subnanosecond temporal resolution. The calibrated method relies on the large contrast associated with magnetization-induced optical second-harmonic generation, permitting measurements with a dynamic range in excess of 25 dB. Calibration is achieved by the determination of the relative magnitude and phase of the essential nonlinear optical tensor components, including those of a magneto-optic origin. Ellipsometric determination of the polarization of the second-harmonic signal, when the magnetization is saturated along four in-plane Cartesian directions, is sufficient to determine the second-order nonlinear tensor components. These four directions represent the two saturated states along the longitudinal and transverse directions of the magnetization, respectively. The tensor components are subsequently used to uniquely determine the in-plane magnetization amplitude and direction.