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.

An all-optical and passively carrier-to-envelope-phase-stabilized (CEP-stabilized) optical parametric chirped pulse amplification (OPCPA) system is demonstrated with sub-250-mrad CEP stability over 11 min and better than 100 mrad over 11 s. This is achieved without any electronic CEP stabilization loop for 160 kHz pulse repetition rate in the few cycle regime.

We report on a two-arm hybrid high-power laser system (HPLS) able to deliver 2 × 10 PW femtosecond pulses, developed at the Bucharest-Magurele Extreme Light Infrastructure Nuclear Physics (ELI-NP) Facility. A hybrid front-end (FE) based on a Ti:sapphire chirped pulse amplifier and a picosecond optical parametric chirped pulse amplifier based on beta barium borate (BBO) crystals, with a cross-polarized wave (XPW) filter in between, has been developed. It delivers 10 mJ laser pulses, at 10 Hz repetition rate, with more than 70 nm spectral bandwidth and high-intensity contrast, in the range of 1013:1. The high-energy Ti:sapphire amplifier stages of both arms were seeded from this common FE. The final high-energy amplifier, equipped with a 200 mm diameter Ti:sapphire crystal, has been pumped by six 100 J nanosecond frequency doubled Nd:glass lasers, at 1 pulse/min repetition rate. More than 300 J output pulse energy has been obtained by pumping with only 80% of the whole 600 J available pump energy. The compressor has a transmission efficiency of 74% and an output pulse duration of 22.7 fs was measured, thus demonstrating that the dual-arm HPLS has the capacity to generate 10 PW peak power femtosecond pulses. The reported results represent the cornerstone of the ELI-NP 2 × 10 PW femtosecond laser facility, devoted to fundamental and applied nuclear physics research.

We present a novel mid-IR source based on optical parametric chirped pulse amplification (OPCPA) generating 96 fs pulses (9.0 cycles) at 3.2 mm with an energy of 1.2 microJ, at a repetition rate of 100 kHz. The amplified spectrum supports a minimum Fourier transform limited pulse duration of 45 fs, or 4.2 cycles. Our use of OPCPA allows the direct amplification of few-cycle pulses at this mid-IR wavelength, and is inherently scalable to higher energies. The seed source for the system is based on difference frequency generation (DFG) between two outputs of the same fibre laser: this source is expected to be intrinsically CEP stable.

No abstract

We demonstrate efficient optical parametric amplification and generation in a gas-filled hollow-core fiber of near-infrared pulses, peaked at 1.4 microm wavelength, with 5 microJ energy and 45 fs duration at the fiber output. Numerical simulations confirm that the OPA is phase matched through excitation of higher-order fiber modes.

We report on the shortest pulses to date from a mid-IR optical parametric chirped pulse amplification: 67 fs duration with 3.8 μJ energy operating at 3.2 μm. The system is all solid state and diode pumped and operates at 100 kHz with unprecedented power stability of 0.75%rms over 30 min.

We demonstrate the validity of the Shackled-frequency-resolved-optical-gating technique for the complete characterization, both in space and in time, of ultrashort optical pulses that present strong angular dispersion. Combining a simple imaging grating with a Hartmann-Shack sensor and standard frequency-resolvedoptical-gating detection at a single spatial position, we are able to retrieve the full spatiotemporal structure of a tilted pulse.