Luis Aina, AlfredoPeřina, J.2023-06-202023-06-201996-031050-294710.1103/PhysRevA.53.1886https://hdl.handle.net/20.500.14352/59730© 1996 The American Physical Society. We would like to thank Professor V. Peřinová and Dr. A. Lukš for carefully reading the manuscript. A.L. also acknowledges the support of a grant from the Ministerio Español de Educación y Ciencia and the kind hospitality from the Optics Department of the Palacký University.The states generated from the vacuum in two parametric down-conversion crystals with aligned idler beams are studied. It is shown that after a measurement of the photon number in some of the modes, the emerging states can be related to SU(2) and SU(1,1) coherent acid minimum-uncertainty states.engjournal articlehttp://dx.doi.org/10.1103/PhysRevA.53.1886http://journals.aps.org/open access535Quantum-opticsInterferenceÓptica (Física)2209.19 Óptica Física