Spin-noise spectrum in a pulse-modulated field.

Abstract

We measure the spin noise spectrum (SNS) of a thermal Rubidium vapor in a pulse-modulated transverse magnetic field and develop a simple theory to describe the main structure of the SNS. Notably, when the pulse area is equal to π, the SNS consists of resonances centered at half-odd-integer multiples of the modulation frequency, while revealing the spin dynamics of the system in a zero field. Our study opens a promising way of studying zero-field spin dynamics by spin noise spectrum free from any low-frequency environmental disturbances.