Picosecond dynamics of spin-related optical nonlinearities in InxGa1−xAs multiple quantum wells at 1064 nm

Abstract

Light-induced absorption and diffraction measurements of resonantly excited 10-nm-width InGaAs multiple quantum wells have been carried out, using circularly polarized beams at 1064 nm. Spin relaxation time τs≃280±15 ps has been determined by monitoring dynamics of light absorption bleaching at 0.04 mJ/cm2, while a nonlinearly compressed spin component in diffraction varied from 220±20 ps to 115±15 ps with excitation. The kinetics of carrier grating with randomized spins allowed the determination of the bipolar diffusion coefficient D=11.5 cm2/s, hole mobility of 230 cm2/V s, and carrier lifetime τR=0.73–1 ns.