Measurement-induced nonclassical states from a coherent state heralded by Knill–Laflamme–Milburn-type interference

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We theoretically generate nonclassical states from a coherent state heralded by Knill–Laflamme–Milburn (KLM)-type interference. Injecting a coherent state in signal mode and two single-photon sources in the other two auxiliary modes of KLM-type interferometry, a broad class of useful nonclassical states is obtained in the output signal port after making two single-photon-counting measurements in the two output auxiliary modes. The nonclassical properties, in terms of the antibunching effect and the squeezing effect as well as the negativity of the Wigner function, are studied in detail by adjusting the interaction parameters. The results show that the input coherent state can be transformed into non-Gaussian states with higher nonclassicality after measurement induction. The maximum squeezing of our generated states is about 1.97928 dB.