High-field mid-infrared pulses derived from frequency domain optical parametric amplification

Abstract

We present a novel approach for scaling the peak power of mid-infrared laser pulses with few-cycle duration and carrier-to-envelope phase stabilization. Using frequency domain optical parametric amplification (FOPA), selective amplification is performed on two spectral slices of broadband pulses centered at 1.8 µm wavelength. In addition to amplification, the Fourier plane is used for specific pulse shaping to control both the relative polarization and the phase/delay between the two spectral slices of the input pulses. At the output of the FOPA, intrapulse difference frequency generation provides carrier-envelope phase stabilized twocycle pulses centered at 9.5 µm with 25.5 µJ pulse energy. The control of the carrier-envelope phase is demonstrated through the dependence of high harmonic generation in solids. This architecture is perfectly adapted to be scaled in the future to high average and high peak 1 powers using picosecond Ytterbium laser technologies.

Characterizing the carrier-envelope phase stability of mid-infrared laser pulses by high harmonic generation in solids

“…Second, the relative delay and polarization of these two spectral slices are controlled using a window and a half waveplate installed in the Fourier plane of the FOPA for shaping the pulses [48]. At the output of the FOPA, intrapulse DFG is performed between two spectral slices, centered respectively at 1.7 and 1.95 m, in a z-cut gallium selenide (GaSe) crystal whose thickness is 750 m. Finally, a long pass filter (LP6715, Spectrogon) selects only the spectral components above 6.7 m. Using this approach, we have recently demonstrated the generation of high-field CEP stable mid-IR pulses centered at 9.5 m with a duration of two cycles and an energy of 25.5 J (±3.5% rms, obtained from statistics of single-shot pulse energy measurements) [28].…”

“…Here, in the FOPA setup, we control this delay with the rotation of a compensating window placed in the optical path of one spectral slice of the broadband pulses (see ref. [28,48]), thus providing a direct control of the waveform of the mid-IR pulses.…”

“…In this work, the mid-IR waveform is tuned by varying the delay between the two spectral slices that drive the DFG process [28]. In the FOPA setup, the polarization of the 1.95 m spectral slice is rotated by a half wave plate.…”

“…Recently, the generation of octave (and beyond) spanning spectra and CEP stabilized femtosecond pulses at long wavelengths towards the mid-IR spectral range has become a very active field driven by a wide variety of applications, at both low repetition rate for high energy pulses [20,[26][27][28] and high repetition rate for high average power [29][30][31][32]. For example, such high energy mid-infrared (IR) pulses are promising to extend the generation of attosecond pulses towards the soft X-rays through HHG in gas [33][34][35]; to provide new tools for studying condensed matter physics such as HHG in solids [36,37] and for the sub-cycle control of electronic dynamics in low bandgap materials [38]; as well as to perform photoelectron streaking with a combined large temporal window and a high temporal resolution [39].…”

Single-shot phase-matching free ultrashort pulse characterization based on transient absorption in solids

“…FROSt is a phase-matching free pulse characterization technique associating transient absorption to ptychographic reconstruction for pulse retrieval. So far, it has been used in a scanning manner for the characterization of broadband pulses with central wavelength from the near-infrared to the mid-infrared, such as few-cycle pulses at 10 µm derived from an optical parametric amplifier [15]. However, for many experiments, it is crucial to obtain the pulse information in a single shot, whether it is to obtain a real-time post-treatment and feedback or to be used with low repetition rate laser systems.…”