Spin Optics Laboratory, St. Petersburg State University, 198504 St. Petersburg, Russia.
Phys Rev Lett. 2013 Apr 26;110(17):176601. doi: 10.1103/PhysRevLett.110.176601. Epub 2013 Apr 23.
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].
处于热力学平衡的磁化强度的自旋系统的自发波动（自旋噪声）表现为探测光的法拉第旋转中的噪声。我们表明，这种噪声在光学频谱上的相关特性可以提供关于自旋系统组成的明确信息，而这对于传统的线性光学来说是很难获得的。这种自旋噪声的光学光谱学，例如，允许我们清楚地区分与不同自旋子系统相关的光学跃迁，分辨在通常的光学光谱中不可分辨的光学跃迁，明确地区分均匀和非均匀展宽的光学带，并评估非均匀展宽的程度。这些新的可能性通过理论计算和具有不同程度的光学跃迁非均匀展宽的顺磁体的实验来演示[41K 原子蒸气和单电荷（In，Ga）As 量子点]。
