Butler, T.P.T.P.ButlerGerz, D.D.GerzHofer, C.C.HoferXu, J.J.XuGaida, C.C.GaidaHeuermann, T.T.HeuermannGebhardt, M.M.GebhardtVamos, L.L.VamosSchweinberger, W.W.SchweinbergerGessner, J.A.J.A.GessnerSiefke, T.T.SiefkeHeusinger, M.M.HeusingerZeitner, U.U.ZeitnerApolonski, A.A.ApolonskiKarpowicz, N.N.KarpowiczLimpert, J.J.LimpertKrausz, F.F.KrauszPupeza, I.I.Pupeza2022-03-052022-03-052019https://publica.fraunhofer.de/handle/publica/25834610.1364/OL.44.0017302-s2.0-85063932931We report a coherent mid-infrared (MIR) source with a combination of broad spectral coverage (6-18 mm), high repetition rate (50 MHz), and high average power (0.5 W). The waveform-stable pulses emerge via intrapulse difference-frequency generation (IPDFG) in a GaSe crystal, driven by a 30-W-average-power train of 32-fs pulses spectrally centered at 2 mm, delivered by a fiber-laser system. Electro-optic sampling (EOS) of the waveform-stable MIR waveforms reveals their single-cycle nature, confirming the excellent phase matching both of IPDFG and of EOS with 2-mm pulses in GaSe.en620535journal article