Photo-induced polarization rotation in semimagnetic semiconductor quantum wells

Summary form only given.Giant photo-induced Faraday rotations were observed in CdTe-CdMnTe multiple quantum wells when the laser frequency is close to the excitonic resonance, which is enhanced through the quantum confinement. Moreover, we recently demonstrated that large photo-induced polarization rotations (-7 degrees) could be obtained even in the absence of an external magnetic field when using circularly polarized pump pulses. In this paper we present a spectrally and temporally resolved analysis of this phenomenon and show that it results from the combined effect of photo-induced magnetization, many body interactions, and spectral hole burning. The sample contained ten 47 /spl Aring/ thick CdTe wells with 950 /spl Aring/ thick CdMnTe barriers on a CdZrTe substrate.