Generation of high-frequency combs locked to atomic resonances by quantum phase modulation

Abstract

A general mechanism for the generation of frequency combs referenced to atomic resonances is put forward. The mechanism is based on the periodic phase control of a quantum systemʼs dipole response. We develop an analytic description of the combʼs spectral structure, depending on both its atomic and phase-control properties. We further suggest an experimental implementation of our scheme, i.e. generating a frequency comb in the soft x-ray spectral region, which can be realized with currently available techniques and radiation sources. The universality of this mechanism allows the generalization of frequency comb technology to arbitrary frequencies, including the hard x-ray regime, by using reference transitions in highly charged ions.