Saturation absorption studies of intersubband relaxation rates in a p-GaAs/AlGaAs QW using a free electron laser

Intersubband relaxation lifetimes in p-GaAs/AlGaAs quantum wells below the LO-phonon energy measured in a free electron laser experiment

“…Pump-probe experiments provide an estimate of 1 ps relaxation time from the LH1 subband to the HH1 subband in a p-In 0.5 Ga 0.5 As/Al 0.5 Ga 0.5 As QW at energies considerably greater than the LO-phonon energy [11]. A recent saturation-absorption study of this transition for a p-GaAs/AlGaAs QW indicates that the relaxation time exceeds approximately 2 ps [12]. In addition, the effect of band mixing on saturation-absorption in p-type QWs has been considered theoretically [13].…”

“…We have performed time resolved pump and probe experiments using the FELIX free electron laser (FEL) facility at the FOM Institute Rijnhuizen, The Netherlands. This technique and other methods for employing FELs in the evaluation of intersubband lifetimes are now well established [8,12,14,15]. We have measured the dynamics of the LH1 to HH1 transition in two samples at energies below the LOphonon energy.…”

Binding energy and dynamics of Be acceptor levels in AlAs/GaAs multiple quantum wells

“…The pump-probe experiments were conducted with the samples cooled to 4 K in a He continuous-flow cryostat with polypropylene windows. The pump probe experiments were conducted at the FELIX facility using the balanced pump-probe technique first implemented in this wavelength regime by Cole et al [4]. This technique uses two probe pulses, one preceding and one following the pump pulse (with a 40 ns total pulse separation).…”