Improved magnetooptic modulator for ultrafast current pulses

A technique is proposed to improve the optical response of a magnetooptic (MO) modulator. The rate at which a MO modulator can operate is limited by the relatively slow relaxation of electron spin carrier populations within the MO material. This relaxation time can be more than an order of magnitude longer than the excitation time. Using a current pulse guided by a superconducting stripline it is possible to create a magnetic field within an MO material. This magnetic field rapidly excites electron spin carriers, resulting in the rapid polarization rotation of an optical beam. Providing a second current pulse of opposite sign to the system generates a second rapid excitation of opposite sign electron spin carriers and returns the polarization to its initial direction. This push-pull technique has the potential to create picosecond optical pulses and provides for the full utilization of the picosecond response time of MO materials.