Second-harmonic generation by reflection of focused femtosecond-pulse beams from a metal surface with a periodic relief

An experimental investigation was made of nonlinear reflection (accompanied by second-harmonic generation) of focused beams, consisting of pulses of about 100 fs duration, from a profiled metal surface. A method for amplifying the nonlinear response (under conditions of generation of the reflected second harmonic) is proposed: it involves enhancement of the local field by a diffraction grating oriented in a special manner when a surface electromagnetic wave is excited.