  We have devised an experimentally realizable model generating twin beam
states whose individual beam photon statistics are varied from thermal to
Poissonian keeping the non-classical mode correlation intact. We have studied
the usefulness of these states for loss measurement by considering three
different estimators, comparing with the correlated thermal twin beam states
generated from spontaneous parametric down conversion or four-wave mixing. We
then incorporated the photon subtraction operation into the model and
demonstrate their advantage in loss estimations with respect to un-subtracted
states at both fixed squeezing and per photon exposure of the absorbing sample.
For instance, at fixed squeezing, for two photon subtraction, up to three times
advantage is found. In the latter case, albeit the advantage due to photon
subtraction mostly subsides in standard regime, an unexpected result is that in
some operating regimes the photon subtraction scheme can also give up to 20%
advantage over the correlated Poisson beam result. We have also made a
comparative study of these estimators for finding the best measurement for loss
estimations. We present results for all the values of the model parameters
changing the statistics of twin beam states from thermal to Poissonian.
