Illustration from Scientific Research

Schematic of the experiment. A thin Al 2 O 3 crystal is placed on top and next to the exposed side of the GaP (100) detection crystal to completely reflect the 15-μm pump and prevent it from generating a spurious nonlinear optical response in the GaP (100) crystal. The thin Al 2 O 3 crystal also creates a well-defined edge in the mid-infrared pump beam, shaping the photo-excited region into a half-disc of about 375 μm diameter. The expected changes due to the local magnetic field expulsion on photo-excitation are shown in the magnified area on the right. The time-dependent magnetic field is sampled positioning the probe beam in the vicinity of the edge of the photo-excited region.

DOI