|Péter Galajda and Pál Ormos
Institute of Biophysics, Biological Research Centre of the Hungarian Academy of Sciences, Temesvári krt. 62., P.O. Box 521, H-6701 Szeged, Hungary
In the last two decades optical tweezers became an important micromanipulation tool in physics, chemistry and biology. It makes possible to fully control the translational state of certain microscopic objects. Additionally to this we present a simple method to control the orientation of the trapped bodies about the optical axis using the polarization of the trapping beam. Moreover, our simple model calculations suggest that the method can be used to measure microscopic torques acting on the trapped objects making it possible to determine e. g. the torsional properties of filamentous giant molecules.