Figure shows Raman spectra of corresponding samples laser-annealed at a slightly higher laser intensity of 9%. After one to four coating and annealing steps, only the anatase peaks at 396 cm -1 , 517 cm -1 and 641 cm -1 are observed. However, after the plate has been coated and annealed five times, the anatase signals are strongly diminished and instead two rutile peaks at 441 cm -1 and 609 cm -1 are formed. Apparently, the higher laser intensity in itself is not yet sufficient to promote significant rutile transformation. However, after repeated treatment, the transformation eventually happens, presumably as a result of enough rutile being formed as a primer for phase transformation in prior treatment steps. If the laser intensity is increased further to 10%, rutile transformation is immediately apparent already after the first treatment step. As seen in Figure , only the rutile peaks at 446 cm -1 and 609 cm -1 are readily observable in this case, features attributable to anatase are only seen with very low intensity. The reason for this difference lies in the higher energy available during treatment with 10% laser intensity. This additional energy promotes the conversion of anatase to rutile, as rutile is a more stable phase at higher temperatures and energies. Thus, more intensive treatment favors the formation of rutile, while lower laser intensity favors anatase.