title: Mid-infrared optical frequency combs based on difference frequency generation for molecular spectroscopy.
abstract: Mid-infrared femtosecond optical frequency combs were produced by difference frequency generation of the spectral components of a near-infrared comb in a 3-mm-long MgO:PPLN crystal. We observe strong pump depletion and 9.3 dB parametric gain in the 1.5 μm signal, which yields powers above 500 mW (3 μW/mode) in the idler with spectra covering 2.8 μm to 3.5 μm. Potential for broadband, high-resolution molecular spectroscopy is demonstrated by absorption spectra and interferograms obtained by heterodyning two combs.
authors.forename: Flavio C
authors.initials: FC
authors.lastname: Cruz
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Maser
authors.forename: Todd
authors.initials: T
authors.lastname: Johnson
authors.forename: Gabriel
authors.initials: G
authors.lastname: Ycas
authors.forename: Andrew
authors.initials: A
authors.lastname: Klose
authors.forename: Fabrizio R
authors.initials: FR
authors.lastname: Giorgetta
authors.forename: Ian
authors.initials: I
authors.lastname: Coddington
authors.forename: Scott A
authors.initials: SA
authors.lastname: Diddams