Measurement of the ratio of the cesium<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>D</mml:mi></mml:math>-line transition strengths

Abstract

High-precision laser absorption spectroscopy in a thermal vapor cell is used in the measurement of the ratio of the $D$-line transition strengths in the cesium atom. We find $\mathbf{|}〈{6p}^{2}{P}_{3/2}||\stackrel{\ensuremath{\rightarrow}}{r}||{6s}^{2}{S}_{1/2}〉{\mathbf{|}}^{2}/\mathbf{|}〈{6p}^{2}{P}_{1/2}||\stackrel{\ensuremath{\rightarrow}}{r}||{6s}^{2}{S}_{1/2}〉{\mathbf{|}}^{2}=1.9809(9),$ which compares favorably with the ratio calculated from the most precise lifetime measurements of these states and the predictions of ab initio calculation. We also verify the predictions of impact-regime line-broadening calculations for densities of order ${10}^{18}$ atoms per ${\mathrm{m}}^{3}.$ Theoretical implications and future experimental promise are discussed.