Ultrafast coherent response of semiconductor quantum wells for multisubband excitation

Summary form only given.We study the coherent emission from transitions corresponding to different pairs of electron (e) and heavy (hh) or light (Ih) hole subbands in a 500-A wide GaAs-Al/sub 0.3/Ga/sub 0.7/As quantum well by spectrally resolved transient four wave mixing (FWM). The low-temperature linear absorption spectrum shows exciton transitions between electron and hole subbands with the same quantum number as well as exciton transitions.