We have used the 830 nm, subpicosecond output of a mode‐locked Ti:sapphire laser, together with subpicosecond 3.55 &mgr;m pulses from a synchronously pumped optical parametric oscillator, to perform room‐temperature, time‐resolved, differential transmission measurements on a multiple quantum well structure with AlGaSb barriers and GaInSb/InAs superlattice wells. From these measurements, we have determined a Shockley–Read–Hall rate of 2.4×108s−1and an Auger coefficient of 7×10−27cm6/s. In addition, we estimate the carrier capture efficiency into the wells to be ∼52% and have demonstrated that carrier cooling, cross‐well transport, and capture are complete within ∼10 ps after excitation. ©1996 American Institute of Physics.