M. Gaugitsch et al., MAGNETOOPTIC LIGHT-MODULATION FOR REFRACTION MEASUREMENTS BY THIN IRON FILMS, Journal of magnetism and magnetic materials, 158, 1996, pp. 438-439
The magneto-optical transverse Kerr effect of a 50 nm thin iron film i
s used to modulate (modulation index 3%) Light beams up to 100 kHz. Th
e displacement between two light spots is measured by the time differe
nce of the corresponding photodetector signals. At a total light power
of 5 mu W a local resolution of 29 nm is achieved.