Relative contribution of the electric-field-induced third-order effect to second-harmonic generation in poled, doped, amorphous polymers

Received October 6, 1992; revised manuscript received October 4, 1993; permission to publish received July 6, 1994 A novel approach involving a delay-trigger method and doped, glassy polymers has been developed to determine the contribution of the electric-field-induced third-order effect to the second-order macroscopic susceptibility x(2) of nonlinear optical dyes. A submillisecond, variable time delay is employed for switching on or off the electric poling field with respect to the laser pulse. For the several dyes tested at 30 0C the contribution of the electric-field-induced third-order effect (second-harmonic wavelength = 532 nm) ranges from (6 ± 2)% of (2) 4-(dimethylamino)benzylidenemalononitrile to (20 ± 3)% of x(2) for 4-(dimethylamino)-4'-nitrostilbene.