Hyperfine structure and isotope-shift investigations of atomic nitrogen by saturation spectroscopy

In this work we report a Doppler-free investigation of atomic nitrogen. As a laser source we used a narrow-band semiconductor diode laser emitting in the near infrared. Atomic nitrogen was produced by dissociating N2 molecules in a radio-frequency discharge sustained by helium as a buffer gas. Hyperfine structures and isotope shifts of the transitions 3p 4P1/2-5/2-3s 4P1/2-5/2o were investigated for the two stable isotopes 14N and 15N by using absorption-saturated laser spectroscopy.