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

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 similar to0.1 mA. 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. (C) 2004 American Institute of Physics.