Resonance anomalies in the angular dependences of the conversion efficiency of second harmonic generation in silver island films

Narrow maxima were detected experimentally in the dependences of the efficiency of conversion of radiation to the second harmonic in a silver island film on the angle of incidence of the pump radiation. These maxima were observed at the same angles of incidence as the recently reported minima of the linear reflection coefficient and were due to spatial resonances of a local field in island films.