title: Electromagnetically induced torque on a large ring in the microwave range.
abstract: We report on the exchange of orbital angular momentum between an electromagnetic wave and a 30 cm diameter ring. Using a turnstile antenna in the GHz range, we induce a torque on a suspended copper strip of the order of 10(-8)  N m. Rotations of a few degrees and accelerations up to 4×10(-4) °/s2 are observed. A linear dependence of the acceleration as a function of the applied power is found. There are many applications in the detection of angular momentum in electromagnetics, in acoustics, and also in the magnetization of nanostructures.
authors.affiliation: URU 435 LPL, Université Rennes 1, 35042 Rennes cedex, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Emile
authors.affiliation: UMR CNRS 6164 IETR, Université Rennes 1, 35042 Rennes cedex, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Brousseau
authors.affiliation: UMR CNRS 6251 IPR, Université Rennes 1, 35042 Rennes cedex, France.
authors.forename: Janine
authors.initials: J
authors.lastname: Emile
authors.affiliation: URU 435 LPL, Université Rennes 1, 35042 Rennes cedex, France and UMR CNRS 6164 IETR, Université Rennes 1, 35042 Rennes cedex, France.
authors.forename: Ronan
authors.initials: R
authors.lastname: Niemiec
authors.affiliation: UMR CNRS 6164 IETR, Université Rennes 1, 35042 Rennes cedex, France.
authors.forename: Kouroch
authors.initials: K
authors.lastname: Madhjoubi
authors.affiliation: Swedish Institute of Space Physics, Ångström Laboratory, P.O. Box 537, SE-751 21 Uppsala, Sweden.
authors.forename: Bo
authors.initials: B
authors.lastname: Thide