Stronger entanglement conditions based on redefined Stokes parameters for quantum optical fields

We show that a redefined approach to Stokes parameters for quantum optical fields of varying intensities allows one to formulate more sensitive entanglement conditions. The redefined Stokes parameters characterize average measured polarization, and the effects of intensity fluctuations of the fields are removed. Thus their average values are a statistical ensemble averages of polarization, and not averages of intensity at the exits of polarization analyzers (divided by the total average intensity), as it is in the standard case. We show examples of entanglement conditions, which upon change from old to new Stokes parameters detect entanglement for a significantly broader range of states. Our working example is the (bright) squeezed vacuum.