The bistable mode of second harmonic generation by femtosecond pulses

The possibility of controlling the efficiency of second harmonic generation by femtosecond pulses is demonstrated. By the phase shift in a certain cro ss section of the medium, switching from the low-efficient to the high-effi cient generation state (and vice versa) is realized. The switching contrast in terms of the conversion efficiency is up to 4 (or more) and in terms of the peak intensity at the center of the pulse it is as high as 9. A new cl ass of optical switches based on this effect is suggested. (C) 2001 MAIK "N auka/ Interperiodica".