Generation of sub-half-cycle 10 µm pulses using four-wave mixing through two-color filamentation

Carrier-envelope phase (CEP)-stable sub-cycle mid-infrared (MIR) pulses play an important role to investigate field-sensitive nonlinear processes. In this contribution, we report the generation of sub-half-cycle phase-stable pulses with the carrier wavelength of( ω 1 ) and second harmonic (SH, ω 2 ) of sub-milli joule 35 fs pulses at 800 nm were focused into nitrogen gas at∼10 µm through two-color filamentation in nitrogen [1] . The fundamental atmospheric pressure. Broadband MIR pulses ( ω 0 ) were generated through the four-wave mixing (FWM) process, ω 1 + ω 1 − ω 2 → ω 0 . Typical MIR spectra at four different phase delay lengths between the fundamental and SH.2µm. The input pulses are shown in Fig. 1(a) . The center of mass of the spectrum at zero phase delay lengths is 10 spectrum is spread from 4.90 to 43.1µm (from 2040 to 232cm− 1 ), which corresponds to more than three octaves with full width at tenth maximum. The pulse energy was 0.42µJ, which would be high enough for high harmonic generation in solids.