Geometries for MSHG. (a) Longitudinal configuration in which lies parallel to the plane of incidence and (b) transverse configuration, with perpendicular to the plane of incidence.
Magnetization-induced second-harmonic generation at each interface: air-tantalum, tantalum-Permalloy, and Permalloy-nonmagnet.
Polarization of the second-harmonic generated light as a function of the magnetization state. In the case of a longitudinal magnetization, the second-harmonic polarization rotates (dotted and dashed curves) with respect to the incident polarization , as predicted by Eq. (6). Transverse magnetization changes the intensity (the dash-dotted and solid curves).
The experimental configuration used to probe the two in-plane components of . The average intensity is measured at the photomultiplier tube (PMT). The polarization rotation is determined by modulation with a photoelastic modulator and measurement of the modulation signal by means of a lock-in amplifier. Note that in this figure the sample is rotated by 90° to show the various magnetization directions.
(Color online) The change in intensity is plotted as a function of the photoelastic modulator retardation. The magnetization is switched between the two saturated states of ( and ).
Two hard-axis dependencies as measured by MSHG, at which a prior calibration was performed to calculate the in-plane magnetization components from the data for a sample with low contrast and large contrast (inset). The low contrast measurements were performed on a multilayer on glass, where the numbers indicate the individual layer thickness in nanometer. The high contrast measurements were performed on a multilayer on sapphire. Both measurements were done by probing through the substrates.
Experimental pump-probe setup. The magnetic pulse field is generated by an electronic pulse generator. The time delay between pump and probe is controlled by a delay generator.
(a) Calibrated in-plane vector components of the magnetization motion after excitation with a steplike magnetic field pulse. The bias field was . (b) Reconstruction of the excitation angle (circles) and absolute value (squares) of the magnetization from the two in-plane components shown in (a).
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