  We perform experimental quantum polarimetry using a heralded single photon to
analyze the optical activity of linearly polarized light traversing a chiral
medium. Three kinds of estimators are considered to estimate the concentrations
of sucrose solutions from measuring the rotation angle of the linear
polarization of the output photons. Through repetition of independent and
identical measurements performed for each individual scheme and different
concentration sucrose solutions, we compare the estimation uncertainty among
the three schemes. The results are also compared to classical benchmarks for
which a coherent state of light is taken into account. The quantum enhancement
in the estimation uncertainty is evaluated and the impact of experimental and
technical imperfections is discussed. In this work, we lay out a route for
future applications relying on quantum polarimetry.
