Аннотации:
High-finesse frequency combs (HFC) with large ratio of the frequency spacing to the width of the spectral
components have demonstrated remarkable results in many applications such as precision spectroscopy and
metrology. We found that low-finesse frequency combs having very small ratio of the frequency spacing to the
width of the spectral components are more sensitive to the exact resonance with absorber than HFC. Our method
is based on time domain measurements reviling oscillations of the radiation intensity after passing through an
optically thick absorber. Fourier analysis of the oscillations allows to reconstruct the spectral content of the comb.
If the central component of the incident comb is in exact resonance with the single line absorber, the contribution
of the first sideband frequency to oscillations is exactly zero. We demonstrated this technique with -photon
absorption by Mossbauer nuclei providing the spectral resolution beyond the natural broadening.
