We have investigated the $4s {}^{2}{S}_{1/2}\ensuremath{\rightarrow}5p {}^{2}{P}_{1/2}$ transition ( ${D}_{1}$ line) of the potassium isotopes $^{39}\mathrm{K}$ , $^{40}\mathrm{K}$ , and $^{41}\mathrm{K}$ using Doppler-free laser saturation spectroscopy. Our measurements reveal the hyperfine splitting of the $5p {}^{2}{P}_{1/2}$ state of $^{40}\mathrm{K}$ , and we have determined the specific mass shift and the nuclear field shift constants for the blue (405 nm) ${D}_{1}$ line.We have investigated the $4s {}^{2}{S}_{1/2}\ensuremath{\rightarrow}5p {}^{2}{P}_{1/2}$ transition (${D}_{1}$ line) of the potassium isotopes $^{39}\mathrm{K}$, $^{40}\mathrm{K}$, and $^{41}\mathrm{K}$ using Doppler-free laser saturation spectroscopy. Our measurements reveal the hyperfine splitting of the $5p {}^{2}{P}_{1/2}$ state of $^{40}\mathrm{K}$, and we have determined the specific mass shift and the nuclear field shift constants for the blue (405 nm) ${D}_{1}$ line.

arXiv:1103.2908Physical Review AMay 18, 201112 citations

We have investigated the $4s {}^{2}{S}_{1/2}\ensuremath{\rightarrow}5p {}^{2}{P}_{1/2}$ transition (

{D}_{1}

line) of the potassium isotopes

^{39}\mathrm{K}

^{40}\mathrm{K}

, and

^{41}\mathrm{K}

using Doppler-free laser saturation spectroscopy. Our measurements reveal the hyperfine splitting of the

5p {}^{2}{P}_{1/2}

state of

^{40}\mathrm{K}

, and we have determined the specific mass shift and the nuclear field shift constants for the blue (405 nm)

{D}_{1}

line.