Measurement of the ¹³³Cs 6p²P_1/2 state hyperfine structure

We employ crossed-beam laser spectroscopy to measure the hyperfine structure of the 6p ²P_1/2 state of atomic ¹³³Cs (I=7 / 2). A frequency-stabilized Ti:sapphire laser with 1-GHz sidebands excites a thermal atomic cesium beam through the 6s ²S_1/2 F=3,4→6p ²P_1/2 F^′=3,4 resonance transitions at 895 nm. The hyperfine splitting of the excited state is determined from the observed fluorescence spectra. Our result for the 6p ²P_1/2 F^′=3 to F^′=4 hyperfine splitting is 1167.54(32) MHz, yielding a magnetic dipole coefficient of A=291.89(8) MHz. In this Brief Report we also compare our results with previous measurements and theory.