Luis Aina, AlfredoSánchez Soto, Luis Lorenzo2023-06-202023-06-201998-021050-294710.1103/PhysRevA.57.781https://hdl.handle.net/20.500.14352/59708© 1998 The American Physical Society. We wish to thank Professor G. García-Alcaine for a careful reading of the manuscript.Two examples are presented where the observation of the emission in parametric down-conversion leads to its enhancement instead of its inhibition. The improvement is analyzed in terms of the quantum features of the observation.engjournal articlehttp://dx.doi.org/10.1103/PhysRevA.57.781http://journals.aps.org/open access535Phase uncertaintyQuantumStatesLightÓptica (Física)2209.19 Óptica Física