Abstract: A method for changing a polarization of a working laser beam includes generating the working laser beam in a working laser source, and irradiating a Verdet medium of a Faraday rotator using the working laser beam. The method further includes changing a charge carrier density of the Verdet medium by irradiating the Verdet medium using an excitation laser beam, and/or applying an electric field to the Verdet medium using an electrode, and/or changing a temperature of the Verdet medium using a heating element and/or a cooling element.

Abstract: A back surface contact solar cell has a wafer with an anti-reflection layer on the front surface, with an emitter and a back surface field on the back surface, and with contacts, produced using laser ablation, on the back surface, wherein the pitch is at most 800 micrometers. Furthermore provided is a method for producing such a solar cell.

Abstract: In a process for the transition-metal-catalyzed preparation of polymers having a syndiotactic or predominantly syndiotactic structure from vinylaromatic monomers and a process for preparing block copolymers from vinylaromatic monomers and olefinically unsaturated polar monomers, use is made of transition metal compounds of the formula (I) where the substituents and indices have the following meanings: M is scandium, yttrium, lanthanum or a lanthanide metal, R′″ is &mgr;-C3-C20-alkyl, L is a low molecular weight organic compound having Lewis basicity, where n=1 or 0 and at least one n in (I) is 0, m is 1 or 2.