Imaging the spin Hall effect of light inside semiconductors via absorption

The opposite transverse shifts for the right and left circular polarization components of a 100 fs 820 nm linearly polarized pulse focused onto GaAs are observed in situ via absorption. A time-delayed normally incident probe pulse scanned across the excitation spot detects the differential circular dichroism associated with the pump-induced transfer of spin angular momentum from light to electrons. More generally, we show that for a normormally incident probe, one can observe the spin Hall effect for probe light through a variety of pump-induced changes to a material's optical properties. (C) 2009 Optical Society of America