title: Optical spectroscopy of spin noise.
abstract: Spontaneous fluctuations of the magnetization of a spin system in thermodynamic equilibrium (spin noise) manifest themselves as noise in the Faraday rotation of probe light. We show that the correlation properties of this noise over the optical spectrum can provide clear information about the composition of the spin system that is largely inaccessible for conventional linear optics. Such optical spectroscopy of spin noise, e.g., allows us to clearly distinguish between optical transitions associated with different spin subsystems, to resolve optical transitions that are unresolvable in the usual optical spectra, to unambiguously distinguish between homogeneously and inhomogeneously broadened optical bands, and to evaluate the degree of inhomogeneous broadening. These new possibilities are illustrated by theoretical calculations and by experiments on paramagnets with different degrees of inhomogeneous broadening of optical transitions [atomic vapors of 41K and singly charged (In,Ga)As quantum dots].
authors.affiliation: Spin Optics Laboratory, St. Petersburg State University, 198504 St. Petersburg, Russia.
authors.forename: V S
authors.initials: VS
authors.lastname: Zapasskii
authors.forename: A
authors.initials: A
authors.lastname: Greilich
authors.forename: S A
authors.initials: SA
authors.lastname: Crooker
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: G G
authors.initials: GG
authors.lastname: Kozlov
authors.forename: D R
authors.initials: DR
authors.lastname: Yakovlev
authors.forename: D
authors.initials: D
authors.lastname: Reuter
authors.forename: A D
authors.initials: AD
authors.lastname: Wieck
authors.forename: M
authors.initials: M
authors.lastname: Bayer