  We measure the scalar, vector and tensor components of the differential
dynamic polarizability of the strontium intercombination transition at 1064 nm.
We compare the experimental values with the theoretical prediction based on the
most recently published spectroscopic data, and find a very good agreement. We
also identify a close-to-circular `magic' polarization where the differential
polarizability strictly vanishes, and precisely determine its ellipticity. Our
work opens new perspectives for laser cooling optically trapped strontium
atoms, and provides a new benchmark for atomic models in the near infrared
spectral range.
