Mi. Stockman et al., INTERSUBBAND OPTICAL BISTABILITY INDUCED BY RESONANT-TUNNELING IN AN ASYMMETRIC DOUBLE-QUANTUM-WELL, Physical review. B, Condensed matter, 48(15), 1993, pp. 10966-10971
An intrinsic optical bistability in a double quantum well is described
theoretically. The effect is based on the resonant tunneling of elect
rons against the electric-field force (the counterfield electron trans
fer) and is driven and controlled by far-ir radiation exciting an inte
rsubband transition. The theory relies on the density-matrix technique
and takes into account optical intersubband excitation, interwell tun
neling, the relaxation of populations and polarizations, and the mean-
field effects of the transferred electron charge (shifts of the levels
and changes of matrix elements). Hysteresis-type curves are obtained
for both the charge-transfer probability and the optical absorption as
functions of the light intensity. The theory shows the effect to be r
eadily observable under realistic conditions, with the exciting-light
intensity as low as 50 W/cm2.