Observation of optical bleaching at 1.06 μm in AlInAs/AlGaInAs multiple quantum wells

We investigated the growth and optical properties of Al0.48In0.52As/Al0.27Ga0.21In0.52As multiple quantum wells. Conditions were established for the defect-free growth of Al0.48In0.52As by metalorganic vapor phase epitaxy and multiple-quantum-well saturable absorbers were fabricated. Simulation of X-ray diffraction patterns indicated that the interfaces in this system are abrupt without unintentional interface layers. Cross-sectional transmission electron microscopy proved that structural defects are absent for structures exceeding 6 μm in thickness. Room temperature photoluminescence displayed a nearly constant linewidth as the number of quantum-well periods is increased, further attesting to the optical quality of these structures. Using transient pump-probe optical techniques, we measured the absorbance bleaching decay of a saturable absorber. These measurements suggested that the bleaching lifetime is over 100 ns, which should be sufficient for Q-switching solid-state lasers.