Optical absorption of THz-field-driven and dc-biased quantum wells - art. no. 155309

Linear optical absorption in a quantum well driven by a growth-direction-or iented THz electric field is investigated. We show that if in addition to t he THz field a dc bias field is applied to the quantum well, the optical ab sorption becomes much more sensitive to the presence of the THz field, This results in the emergence of multiple replicas in the absorption spectrum o f biased quantum wells for a low-frequency (compared with the subband energ y spacing) THz field. We consider undoped quantum wells and develop an appr oach that allows us to treat nonlinear effects in THz field strength, We di scuss separately the optical absorption due to free-electron-hole pairs and due to excitons.