A series of Ag-doped La0.6Pb0.4MnO3 thin films were grown on vicinal cut substrates by pulsed laser deposition (PLD). Laser-induced thermoelectric voltages (LITV) had been observed in these films, and these LITV signals had been demonstrated to originate from the anisotropic Seebeck effect. By doping Ag to an optimum value, it was found that the peak values (U-P) of the LITV signals were maximized, and the full-width at half-maximum (tau) of the response curves of LITV were minimized at the same time. The figure of merit (F-m) of the device used as photodetector is greatly improved by doping Ag in La0.6Pb0.4MnO3 thin films. The possible reason for these improvements had been well discussed. (C) 2008 Elsevier B.V. All rights reserved.