Photoinduced absorption saturation dynamics of InGaAs quantum dot structure dedicated for wavelength 1070 nm

In this paper, results of investigation of InGaAs quantum dot structure designed as a semiconductor saturable absorber for near-IR are presented. Photoinduced absorption bleaching spectroscopy performed confirm the dedicated wavelength 1070 nm for absorption bleaching of the ground state of quantum dots. Transitions including states from the wetting layer and the ground states have been interpreted to define absorption recovery dynamics on femto- and picosecond time scale. Fast recovery time of absorption was measured for the upper excited energy levels, while the ground state dynamics show relative longer times. Non-degenerate pump-probe technique was applied to investigate the interstate transition dynamics.