MULTISUBBAND INFRARED DRESSING OF EXCITONS IN QUANTUM-WELLS

A formalism is described that self-consistently treats the effects of infrared (ir) coupling fields on the interband quantum-well absorption spectrum when both the e1-e2 and e2-e3 conduction subband transitions are nearly resonant with the ir frequency. For the 8.5-nm-wide GaAs q uantum-well samples typically considered for ir dressing studies, we s how that the simultaneous two-photon coupling of the e1-hh1 and e3-hh1 excitons and the one-photon coupling of all three excitons produces s ignificantly different results than those obtained when the e2-e3 coup ling is neglected. In particular we find that the position and shape o f the dominant e1-hh1 exciton feature each change nonmonotonically, an d saturate with increasing ir intensity. This is in better agreement w ith existing experimental results than previous calculations based on simple e1-e2 coupling.