Hyperfine structure and isotope shifts in near-infrared transitions of atomic nitrogen

Abstract

We have obtained Doppler-free spectra of transitions in the \({2p^2(^3{\rm P}) \ 3s\ {}^4{\rm P}}\) → 2p2(3P) \({3p\ {}^4{\rm P}^{\circ}}\) and \({2p^2(^3{\rm P}) \ 3s\ {}^4{\rm P}}\) → \({2p^2(^3{\rm P}) \ 3p\ {}^4{\rm D}^{\circ}}\) multiplets of atomic nitrogen using saturated absorption spectroscopy. These multiplets consist of respectively of seven and eight transitions, and have center of gravity wavelengths of 821 nm and 869 nm. Values for the hyperfine structure coupling constants of all the upper and lower states for these multiplets were obtained for both 14N and 15N. Isotope shifts of three transitions in each multiplet were also measured, and a significant J-dependence to the shifts was observed.