Abstract

Standard Fourier Transform Spectrometers (FTS) are commonly based on an interferometer (beam splitter and mirrors) with mechanically driven scanning parts. This leads to technical limitations regarding the resolution and scanning speed of the traditional FTS. High resolution requires highly stable and long scanning movements, which makes the study of fast evolving processes difficult. The technology of the Dual Comb Spectrometer (DCS), first introduced by S. Schiller in 2002 [1] permits to overcome this limitation. Here, instead of a long scanning arm, it is a slight difference between the repetition rates of two femtosecond lasers that produces the periodic beating of the frequency combs containing the spectral information of the light. The periodic temporal overlap of the pulse trains occurs within milliseconds and presents a higher sweeping stability than any mechanical scanner. Figure 1 presents simplified schematics of a DCS (left panel).

© 2015 IEEE