A recent work [Pegg et al., Phys. Rev. Lett. 81, 1604 (1998)] showed how to generate a running-wave superposition of zero- and one-photon field states, $C_0|0〉{+C}_1|1〉,$ by physical truncation of the photon number superposition making up a coherent state. Here we discuss the extension of this device to the case of N components: $C_0|0〉{+C}_1|1〉+\cdot \cdot \cdot {+C}_N|N〉.$

• Received 11 August 2000

DOI:https://doi.org/10.1103/PhysRevA.63.055801