Dual-channel spectral interferometry is used to measure the ellipticity, the orientation of the polarization ellipse, and the sense of rotation of the four-wave-mixing signal from a GaAs–AlGaAs multiple quantum well. Each parameter is observed to oscillate dramatically at the heavy-hole–light-hole quantum beat frequency. During each beat period (in the strong quantum beat regime), the ellipticity oscillates twice between linear and almost-circular polarization, the orientation of the polarization ellipse rotates through a complete 180°, and the sense of rotation changes from left- to right-circular polarization.
© 1998 Optical Society of America
Arthur L. Smirl, X. Chen, and O. Buccafusca, "Ultrafast time-resolved quantum beats in the polarization state of coherent emission from quantum wells," Opt. Lett. 23, 1120-1122 (1998)