  A scheme is discussed for measuring Nth-order coherences of two orthogonally
polarized light fields in a single spatial mode at very limited experimental
cost. To implement the scheme, the only measurements needed are the Nth-order
intensity moments after the light beam has passed through two quarter-wave
plates, one half-wave plate, and a polarizing beam splitter for specific
settings of the wave plates. It is shown that this method can be applied for
arbitrarily large N. A set of explicit values is given for the settings of the
wave plates, constituting an optimal measurement of the Nth-order coherences
for any N. For Fock states the method introduced here corresponds to a full
state tomography. Applications of the scheme to systems other than polarization
optics are discussed.
