A. Piskarskas

Powerful femtosecond pulse generation by chirped and stretched pulse parametric amplification in BBO crystal

Abstract Chirped pulses have been parametrically amplified by a factor of ∼2×10 4 without bandwidth limitation in BBO crystal. Pulses were compressed down to 70 fs, and ∼0.9 GW output power has been obtained. A special technique to match temporal profiles of signal and pump pulses was used.

Traveling-wave parametric generation of widely tunable, highly coherent femtosecond light pulses

We report on the generation of ultrashort tunable pulses with a cavityless traveling-wave scheme consisting of a parametric superfluorescence seed source and a parametric amplifier. We show that the traveling-wave approach, with its advantages of simplicity and direct generation of tunable energetic single pulses, can be used in the femtosecond regime, and to this end we discuss the performances that were obtained with pump pulses of ≈1-ps and 200-fs duration at wavelengths of 0.53 and 0.6 μm, respectively. Of particular interest is the β-barium borate-based traveling-wave parametric generator (type-II phase matching), since it offers the possibility of generating nearly transform-limited pulses that are continuously tunable within a wide spectral range to as high as 3 μm in the IR. With a diffraction-limited pump at 0.53 μm. we obtained tunable pulses in a 1.2× diffraction-limited beam, which could be focused, with an f/20 optics lens, to an intensity of 1013 GW/cm2. A temperature-tuned lithium triborate-based femtosecond parametric generator, with its smaller group-velocity dispersion and absence of walk-off, can operate at a pump energy of as low as 30 μJ in a 200-fs pulse.

Multimillijoule chirped parametric amplification of few-cycle pulses

The concept of optical parametric chirped-pulse amplification is applied to attain pulses with energies up to 8 mJ and a bandwidth of more than 100 THz. Stretched broadband seed pulses from a Ti:sapphire oscillator are amplified in a multistage noncollinear type I phase-matched beta-barium borate parametric amplifier by use of an independent picosecond laser with lock-to-clock repetition rate synchronization. Partial compression of amplified pulses is demonstrated down to a 10-fs duration with a down-chirped pulse stretcher and a nearly lossless compressor comprising bulk material and positive-dispersion chirped mirrors.

Progress in chirped pulse optical parametric amplifiers

We discuss the main issues of optical parametric chirped pulse amplification and overview recent progress in the field. Although we distinguish between the two operating modes of modern chirped pulse parametric amplifiers, OPCPA and NOPA, we reveal that both represent the same technique and share a common concept.

Highly efficient parametric conversion of femtosecond Ti:sapphire laser pulses at 1 kHz

Pulses with energies as high as 150 microJ and durations as low as 60 f(s) were generated from 1.1 to 2.6 microm by a traveling-wave parametric converter pumped by femtosecond pulses of a Ti:sapphire laser with chirped-pulse amplification.

Matching of group velocities in three-wave parametric interaction with femtosecond pulses and application to traveling-wave generators

The use of suitable noncollinear phase-matching configurations in type-I (e–oo) parametric interaction greatly improves the group-velocity matching among pump, signal, and idler pulses. A numerical model, well supported by the experiments, shows that the compensation of group-velocity mismatch can be achieved over the entire tuning range for pulses as short as few tens of femtoseconds. A general feature of the noncollinear interaction, the front tilt of the generated pulses, is experimentally investigated for a LiIO3 traveling-wave generator. A novel β-barium borate traveling-wave parametric converter pumped with 130-fs blue pulses from a frequency-doubled amplified Ti:sapphire system provides broad tunability in the visible with pulse durations as low as 90 fs and with a single-pass conversion efficiency as large as 40%.

Conversion of topological charge of optical vortices in a parametric frequency converter

Abstract It is shown that sum-frequency generation of light beams with vortices allows to construct vortices of different topological charges. An optical parametric amplifier enables to produce a vortex with opposite topological charge (to the reverse vortex). In this way, a frequency converter can be seen as a prototype of an optical processor which allows to produce simple arithmetical operations with topological charges of the interacting vortices.

Matching of group velocities by spatial walk-off in collinear three-wave interaction with tilted pulses

We demonstrate that, for tilted pulses, the contribution to group velocity that is due to spatial walk-off can compensate for the group-velocity mismatch in three-wave interactions. With 100-fs, 0.4-Zmicrom pump pulses in beta-barium borate, we obtained efficient parametric generation of collinear superfluorescence tunable in the range from 0.456 to 3.25 microm.

Self-diffraction through cascaded second-order frequency-mixing effects in β-barium borate

The large effective third-order nonlinearity produced by cascaded second-order processes is evidenced by the spatial self-diffraction of two beams interacting in a β-barium borate crystal. In this configuration, both the real and imaginary parts of the induced third-order susceptibility play a role, and the effect reaches its maximum around the phase-matching condition.

Combining effect in a multiple-beam-pumped optical parametric amplifier

We demonstrate highly efficient performance (quantum efficiency as great as 80%) of a degenerate three-beam-pumped optical parametric amplifier (OPA). Such an OPA exhibits a parametric combining effect, as the signal gains its energy from all three pump pulses. The efficiency of the parametric amplification process is defined only by a triple phase-matching geometry and is insensitive to the phase relationship of the pump pulses. We also show that OPA operation is not affected by the number of pump pulses in terms of the energy conversion and the temporal characteristics of the amplified pulse.