Subpicosecond Faraday effect in Cd1−xMnxTe and its application in magneto-optical sampling

Abstract

We present our studies on a subpicosecond Faraday effect in diluted magnetic semiconducting Cd1−xMnxTe single crystals and its application in a magneto-optical (MO) sampling system for time-resolved detection of ultrafast current pulses. The measurements were performed at 10 K. We used the Cd0.38Mn0.62Te crystal as the active MO medium and a low-temperature-grown free-standing GaAs photoconductive switch integrated into a coplanar transmission line as the picosecond electrical pulse generator. We observed subpicosecond MO transients that correspond to the intrinsic MO low-temperature response in the Cd1−xMnxTe system with the high Mn concentration. The current sensitivity of our MO system was found to be ∼0.1mA. We have demonstrated that the MO sampling technique using the Cd0.38Mn0.62Te transducer is as fast as the standard LiTaO3, electro-optical sampling technique and allows for a complementary (magnetic-field component) characterization of electrical picosecond transients in ultrafast switching devices. Observation of the subpicosecond Faraday effect in Cd1−xMnxTe crystals makes them very attractive for ultrafast optical modulators.