Abstract

Optical frequency combs are versatile spectroscopic tool providing excellent accuracy, high spectral purity, and broad spectral coverage at the same time. Direct frequency comb spectroscopy (DFCS) techniques exploits the large number of frequency comb components (comb teeth) to provide a massive set of parallel detection channels and acquire spectroscopic informations. In particular, a lot of interest has been focused on resolving the single comb tooth in DFCS measurements, and two main techniques have been reported so far: the first, based on virtually-imaged phased arrays (VIPA), and the second so-called “dual-comb” spectroscopy [1,2]. We present a new DFCS technique with comb-tooth level resolution, based on the frequency dependence of the speckle pattern generated at the output of a multi-mode fiber [3].

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