“…During photoluminescent studies of SiO 2 films implanted with Si, C, S and Sn ions carried out at DESY (beamline I, SUPERLUMI station), unusual excitation spectra containing a series of regularly spaced bands (oscillations) of similar widths were observed (Zatsepin et al, 2009(Zatsepin et al, , 2012aBuntov et al, 2011). It was hypothesized that the origin of these bands was related to interference effects that may occur for the incident electromagnetic waves in films with thicknesses close to the wavelength.…”