We propose and demonstrate an effective mode-filtering technique of non-Gaussian states generated by photon subtraction. More robust non-Gaussian states have been obtained by removing noisy low frequencies from the original mode spectrum. We show that non-Gaussian states preserve their nonclassicality after quantum teleportation to a higher degree when they have been mode filtered. This is indicated by a stronger negativity, $-0.033\pm 0.005$, of the Wigner function at the origin, compared to $-0.018\pm 0.007$ for states that have not been mode filtered. This technique can be straightforwardly applied to various kinds of photon-subtraction protocols and can be a key ingredient in a variety of applications of non-Gaussian states, especially teleportation-based protocols toward universal quantum information processing.

• Received 8 March 2012

DOI:https://doi.org/10.1103/PhysRevA.85.053824