Measurement of the ²⁰⁻²²Ne ³P₂-³D₃ transition isotope shift using a single, phase modulated laser beam

We develop a simple technique to accurately measure frequency differences between far lying resonances in a spectroscopy signal using a single laser. This technique was used to measure the isotope shift of the cooling transition of metastable neon for the result of $1626.264(79)$ MHz. The most accurate determination of this value to date.