Calculation of ionization in direct-frequency comb spectroscopy

Abstract

Direct-frequency comb spectroscopy (DFCS) is currently the highest-resolution absolute frequency spectroscopic technique known. In general, one does DFCS by scanning the repetition rate, f rep , of a comb laser and measuring fluorescence from the excited states of the species under study. The technique has already been successfully characterized by a theoretical model that starts with the optical Bloch equations and, with a few simplifying assumptions converts them into linear coupled iterative equations. In the present work we build on that successful model to predict the characteristics of the ion yield from photoionization by the comb laser, as a function of f rep . We show that the ion spectrum yields the same atomic structure as the fluorescence spectra, but with greater efficiency.

Measurement of ionization in direct frequency comb spectroscopy

“…In a recently published theoretical study of frequency comb light interacting with 87 Rb 10 Lomsadze et al computed the relative populations of the 5s, 5p, 5d, and the continuum states. It was found that the structure of the ion spectrum was essentially identical to that of the 5d, and that the ion population was substantially greater.…”