7  μm, ultrafast, sub-millijoule-level mid-infrared optical parametric chirped pulse amplifier pumped at 2  μm

Abstract

We present a novel all-fiber pumped OPCPA architecture to generate self-CEP stable, sub-8 optical cycle duration pulses at 7-micron wavelength approaching millijoulelevel pulse energy at 100 Hz repetition rate. The system yields a peak power of 1.1 GW and, if focused to the diffraction limit, would reach a peak intensity of 7x10 14 W/cm 2. The OPCPA is pumped by a 2-micron Ho:YLF chirped pulse amplifier to leverage the highly efficient and broadband response of the nonlinear crystal ZGP. The 7-micron seed at 100 MHz is generated via DFG from an Er:Tm:Ho multi-arm fiber frequency comb and a fraction of its output optically injects the Ho:YLF amplifier. While the pulse bandwidth at 7 micron is perfectly suited for nonlinear and spectroscopic applications, current parameters offer, for the first time, the possibility to explore strong field physics in an entirely new wavelength range with a ponderomotive force 77 times larger than from an 800 nm source. The overall OPCPA system is very compact and provides a new tool for investigations directly in the molecular finger print region of the electromagnetic spectrum or to drive high harmonic generation to produce fully coherent X-rays in the multi-keV range and possibly zeptosecond temporal waveforms.

Kagome-fiber-based pulse compression of mid-infrared picosecond pulses from a Ho:YLF amplifier

“…For example, high-energy ultrashort long-wavelength pulses permit the study of novel regimes in photoionization of gases [2,3], including the breakdown of the dipole approximation [4] and the wavelength dependence of recollision physics [5,6], and the investigation of non-perturbative strong-field effects in solids such as the dynamical Franz-Keldysh effect [7,8] and high-order harmonic generation (HHG) from Bloch oscillations [9,10]. MIR optical parametric amplifiers (OPAs), pumped by sub-ps mJ-level 2 μm sources [11], optionally followed by filamentation and pulse self-compression in dielectrics [12,13], provide a direct path to such experiments. Moreover, when properly scaled in pulse energy to the multimJ level, IR pulses even permit the realization of bright coherent tabletop HHG sources in the water-window and keV x-ray region [14].…”

“…Hence, pumping of non-oxide nonlinear crystals with 2 μm laser sources with mJ-level energy and sub-ps pulses are preferred for generating stable and coherent white-light continua as seed for MIR OPAs featuring self-CEP stabilization of the idler [22,23]. Recently, MIR OPA pumped from a holmium laser has been demonstrated [11,24]. However, due to the long pulse duration, seed source was derived from either difference frequency generation or from OPA at 1 μm, which adds extra complexity.…”

Power-scalable subcycle pulses from laser filaments

“…With the advent of efficient and convenient parametric sources of ultrashort pulses in the mid-infrared1314151617181920, the range where many solid-state materials exhibit anomalous dispersion, interesting and practically promising scenarios of filamentation-assisted pulse compression in the regime of anomalous dispersion have been realized212223242526, opening the routes toward compact all-solid-state sources of few-cycle2122, single-cycle27, and even subcycle28 pulses in the mid-infrared. If scaled from pulse energies of a few microjoules to tens of millijoules, these methods of pulse compression would ideally address the needs of rapidly developing technologies of short-pulse generation in the mid-infrared2029.…”

Long-wave infrared generation from femtosecond and picosecond optical parametric oscillators based on orientation-patterned gallium phosphide

“…Zinc germanium phosphide (ZnGeP 2 or ZGP) requires a pump laser with 1.9-µm wavelength or higher, meaning less mature laser sources must be used. It has been used to generate high energy pulses in an optical parametric amplifier between 6 and 7.5 µm [10].…”