Regular Article

Cesium alignment produced by pumping with unpolarized light^★

¹ Physics Department, University of Fribourg, Chemin du Musée 3, 1700 Fribourg, Switzerland
² Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, P.R. China
³ University of Chinese Academy of Sciences, Beijing 100049, P.R. China

^a e-mail: yongqi.shi@unifr.ch

Received: 9 March 2018
Received in final form: 19 March 2018
Published online: 30 April 2018

Abstract

We demonstrate optical pumping on the four hyperfine components of the Cs D₁ transition by unpolarized (UPL) resonant laser light. The evidence is based on the reduction of the absorption coefficients κ₀ with increasing light power P in an uncoated Cs vapor cell with isotropic spin relaxation. For comparison we perform the same quantitative κ₀(P) measurements with linearly-polarized light (LPL) and circularly-polarized light (CPL). We find that our previously published algebraic expressions give an excellent description of all experimentally recorded induced transparency signals. Based on this we can make reliable absolute predictions for the power dependence of the spin orientation and alignment produced by pumping with LPL, CPL and UPL.