  Stokes parameters are a standard tool in quantum optics. They involve
averaged intensities at exits of polarizers. If the overall measured intensity
fluctuates, as e.g. for states with undefined photon numbers, the instances of
its increased value contribute more to the parameters. One can introduce
normalized quantum Stokes operators. Operationally, for a given single run of
the experiment, their values are differences of measured intensities (or photon
numbers) at the two exits of a polarizer divided by their sum. Effects of
intensity fluctuations are removed. Switching to normalized Stokes operators
results in more sensitive entanglement conditions. We also show a general
method of deriving an entanglement indicator for optical fields which use
polarization correlations, which starts with any two-qubit entanglement
witness. This allows to vastly expand the family of such indicators.
