title: Spin noise explores local magnetic fields in a semiconductor.
abstract: Rapid development of spin noise spectroscopy of the last decade has led to a number of remarkable achievements in the fields of both magnetic resonance and optical spectroscopy. In this report, we demonstrate a new - magnetometric - potential of the spin noise spectroscopy and use it to study magnetic fields acting upon electron spin-system of an n-GaAs layer in a high-Q microcavity probed by elliptically polarized light. Along with the external magnetic field, applied to the sample, the spin noise spectrum revealed the Overhauser field created by optically oriented nuclei and an additional, previously unobserved, field arising in the presence of circularly polarized light. This "optical field" is directed along the light propagation axis, with its sign determined by sign of the light helicity. We show that this field results from the optical Stark effect in the field of the elliptically polarized light. This conclusion is supported by theoretical estimates.
authors.affiliation: St.-Petersburg State University, Spin Optics Laboratory, Peterhof, St.-Petersburg 198504, Russia.
authors.forename: Ivan I
authors.initials: II
authors.lastname: Ryzhov
authors.affiliation: St.-Petersburg State University, Spin Optics Laboratory, Peterhof, St.-Petersburg 198504, Russia.
authors.forename: Gleb G
authors.initials: GG
authors.lastname: Kozlov
authors.affiliation: Ioffe Institute of the RAS, Sector of quantum coherent phenomena, St.-Petersburg 194021, Russia.
authors.forename: Dmitrii S
authors.initials: DS
authors.lastname: Smirnov
authors.affiliation: St.-Petersburg State University, Spin Optics Laboratory, Peterhof, St.-Petersburg 198504, Russia.|Ioffe Institute of the RAS, Sector of quantum coherent phenomena, St.-Petersburg 194021, Russia.
authors.forename: Mikhail M
authors.initials: MM
authors.lastname: Glazov
authors.affiliation: St.-Petersburg State University, Resource Center "Nanophotonics", Peterhof, St.-Petersburg 198504, Russia.
authors.forename: Yurii P
authors.initials: YP
authors.lastname: Efimov
authors.affiliation: St.-Petersburg State University, Resource Center "Nanophotonics", Peterhof, St.-Petersburg 198504, Russia.
authors.forename: Sergei A
authors.initials: SA
authors.lastname: Eliseev
authors.affiliation: St.-Petersburg State University, Resource Center "Nanophotonics", Peterhof, St.-Petersburg 198504, Russia.
authors.forename: Viacheslav A
authors.initials: VA
authors.lastname: Lovtcius
authors.affiliation: St.-Petersburg State University, Resource Center "Nanophotonics", Peterhof, St.-Petersburg 198504, Russia.
authors.forename: Vladimir V
authors.initials: VV
authors.lastname: Petrov
authors.affiliation: St.-Petersburg State University, Spin Optics Laboratory, Peterhof, St.-Petersburg 198504, Russia.|Ioffe Institute of the RAS, Laboratory of Semiconductor Optics, St.-Petersburg 194021, Russia.
authors.forename: Kirill V
authors.initials: KV
authors.lastname: Kavokin
authors.affiliation: St.-Petersburg State University, Spin Optics Laboratory, Peterhof, St.-Petersburg 198504, Russia.|University of Southampton, Department of Physics &Astronomy, Southampton SO17 1BJ, United Kingdom.
authors.forename: Alexey V
authors.initials: AV
authors.lastname: Kavokin
authors.affiliation: St.-Petersburg State University, Spin Optics Laboratory, Peterhof, St.-Petersburg 198504, Russia.
authors.forename: Valerii S
authors.initials: VS
authors.lastname: Zapasskii