2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/124715The photon splitting gamma -> gamma gamma in a time-independent and inhomogeneous magnetized background is considered when neutral and ultralight spin-0 particles are coupled to two-photons. Depending on the inhomogeneity scale of the external field, resonant photon splitting can occur. If an optical laser crosses a magnetic field of few Tesla with typical inhomogeneity scale of the order of the meter, a potentially observable rate of photon splittings is expected for the PVLAS range of couplings and masses.7 pages, 2 included eps figures, two references added, minor typos correctedHigh Energy Physics - PhenomenologyAstrophysicstext