Absorption Saturation of Intersubband Transition in InGaAs/AlAsSb Quantum Well Characterized by Absorption Spectral Analysis

Abstract
A lineshape analysis is carried out to deduce the homogeneous linewidth from temperature dependent absorption spectra on the intersubband transitions in InGaAs/AlAsSb quantum wells. Using this linewidth and the pump-probe relaxation time (≈ 2.1 ps) at room temperature, we estimate the saturation intensity to be 52±5 MW/cm2 which shows an agreement with the value obtained from a saturation measurement using a femtosecond laser.