title: Few-photon heterodyne spectroscopy.
abstract: We perform a high-resolution Fourier transform spectroscopy of optical sources in the few-photon regime based on the phenomenon of two-photon interference in a beam splitter. From the heterodyne interferogram, between test and reference sources, it is possible to obtain the spectrum of the test source relative to that of the reference. The method proves to be a useful asset for spectral characterization of faint optical sources below the range covered by classical heterodyne beating techniques.
authors.forename: G C
authors.initials: GC
authors.lastname: Amaral
authors.forename: T
authors.initials: T
authors.lastname: Ferreira da Silva
authors.forename: G P
authors.initials: GP
authors.lastname: Temporão
authors.forename: J P
authors.initials: JP
authors.lastname: von der Weid