IN-WELL SCREENING NONLINEARITIES IN PIEZOELECTRIC MULTIPLE-QUANTUM WELLS

The contribution of the in-well screening of the piezoelectric field t o the nonlinear optical response of a [111]-oriented strained InGaAs/G aAs multiple quantum well is separated from, and compared to, that ass ociated with the out-of-well screening and with bleaching by using pic osecond nondegenerate differential transmission techniques. These meas urements demonstrate that the per-carrier nonlinearity associated with the in-well screening is smaller than that associated with the out-of -well screening by a factor roughly equal to the number of wells. (C) 1995 American Institute of Physics.