Generation of the second harmonic of femtosecond pulses on reflection from a metal surface: amplification due to periodic modulation of the relief

It is observed experimentally that the optical second-harmonic generation signal produced when femtosecond laser pulses are reflected from a metal surface increases more than 100-fold when a specially chosen periodic relief that gives quasiresonance excitation of a surface electro-magnetic wave is depoited on the surface. Pis’ma Zh. éksp. Teor. Fiz. 63, No. 3, 155–159 (10 February 1996)