  Postselected von Neumann measurement characterized by postselection and weak
value has been found potential applications in quantum metrology and, solved
plenty of fundamental problems in quantum theory. As an application of this new
measurement technique in quantum optics, its effects on the features of
single-mode radiation fields such as coherent state, squeezed vacuum state and
Schrodinger cat sate are investigated by considering full-order effects of
unitary evolution. The results show that the conditional probabilities of
finding photons, second-order correlation functions, Q-factors and squeezing
effects of those states after postselected measurement significantly changed
compared with corresponding initial pointer states, respectively.
