Enhanced Optical Kerr Signal of GaAs/AlAs Multilayer Cavity with InAs Quantum Dots Embedded in Strain-Relaxed Barriers

Abstract

Using time-resolved optical measurements, a strong, ultrafast optical Kerr signal was demonstrated in a GaAs/AlAs multilayer cavity containing self-assembled InAs quantum dots (QDs) embedded in strain-relaxed InGaAs barrier layers. The large optical nonlinearity of the resonant InAs QDs in the half wavelength (λ/2) cavity layer is further enhanced by the strong cavity effect. Although only two layers of InAs QDs were inserted in the λ/2 layer, the optical Kerr signal intensity was 60 times larger than that of a GaAs λ/2 cavity. The response time of the optical Kerr signal was less than 1 ps, which was much faster than the decay time (15 ps) of optically generated carriers in the InAs QDs.