  Spin noise spectroscopy has become a widespread technique to extract
information on spin dynamics in atomic and solid-state systems, in a
potentially non-invasive way, through the optical probing of spin fluctuations.
Here we experimentally demonstrate a new approach in spin noise spectroscopy,
based on the detection of single photons. Due to the large spin-dependent
polarization rotations provided by a deterministically-coupled quantum
dot-micropillar device, giant spin noise signals induced by a single-hole spin
are extracted in the form of photon-photon cross-correlations. Ultimately, such
a technique can be extended to an ultrafast regime probing mechanisms down to
few tens of picoseconds.
