Microsphere-assisted super-resolution magneto-optic imaging*

The diffraction limit [1] is a fundamental barrier in optical imaging. It can be surpassed by the photonic nanojet phenomenon, generated by a lens-like dielectric micro-object [2]. Microspheres have been demonstrated as a powerful platform to challenge the diffraction limit by creating a virtual image with enhanced resolution and magnification [3,4]. Here we report on wide-field MOKE (Magneto-Optical Kerr effect) measurements harnessing this resolution enhancement. In-plane and perpendicular magnetized domains, probed with the longitudinal and polar Kerr effects, respectively, are imaged at increase spatial resolution. Our findings may serve as a way to combine the advantages of fast time resolution and versatile sample environment of optical measurements with smaller length scales.
[1] Lord Rayleigh, Philosophical Magazine Series 5, 8(49):261– 274 (1879)
[2] Z. Chen, A. Taflove & V. Backman Optics Express, 12(7), 1214 (2004)
[3] Z. Wang, W. Guo, L. Li et al., Nature Communications, 2(1), 218 (2008)
[4] G. Huszka & M. A. M. Gijs, (2018) Scientific Reports, 8(1), 601 (2018)