Submicrometer resolution far field high sensitivity Kerr microscopy for in-plane magnetization detection

We report that a far field magneto-optical system designed for detecting the off-plane magnetization in polar configuration can also detect the in-plane magnetization, while preserving the high sensitivity by using symmetric illumination and photoelastic modulation, even though the optical axis of the system is vertical to the sample surface. The spatial resolution can reach 500 nm at 514 nm in wavelength. The in-plane sensitivity can be eliminated by using an aperture to remove the off-axis obliquely incident light generated by the high numerical aperture objective lens that focuses the laser beam onto the sample surface.