Linear optical implementation of a single mode quantum filter and generation of multi-photon polarization entangled state

Abstract

We propose a scheme to implement a single-mode quantum filter, which selectively eliminates the one-photon state in a quantum state $\alpha |0>+\beta |1>+\gamma |2>$. The vacuum state and the two photon state are transmitted without any change. This scheme requires single-photon sources, linear optical elements and photon detectors. Furthermore we demonstrate, how this filter can be used to realize a two-qubit projective measurement and to generate multi-photon polarization entangled states.

revision submitted to PRA