C. Solcia

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%.

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.

Visible pulses of 100 fs and 100 μJ from an upconverted parametric generator.

Upconversion by sum-frequency and second-harmonic generation of pulses from a Ti:sapphire-pumped parametric generator provides 50-120 μJ, sub-100 fs, bandwidth-limited pulses at 470-700 nm.

Efficient conversion of femtosecond blue pulses by travelling-wave parametric generation in non-collinear phase matching

Abstract The matching of group velocities achieved in non-collinear three-wave interaction is shown to yield efficient parametric conversion of femtosecond pulses from a frequency-doubled amplified Ti:sapphire laser. Tunability in the whole visible range, pulse duration of 90 fs and single-pass energy conversion efficiencies as large as 40% have been obtained in b-BaB 2 O 4 .

A collinearly phase-matched parametric generator/amplifier of visible femtosecond pulses

We report on the generation and amplification of ultrashort pulses of /spl ap/1.5-/spl mu/J energy, tunable in the visible down to 456 nm, through travelling-wave parametric interaction in a single /spl beta/-BaBO/sub 4/ crystal, operated in type-I phase matching and collinearly pumped by frequency-doubled Ti:sapphire pulses with the fronts suitably tilted to match the group velocities.

All-solid-state picosecond tunable source of near-infrared radiation

A quasi-cw diode-pumped Nd:YAG laser, mode locked by a nonlinear mirror and stabilized by an acousto-optic modulator, has been developed that generates 31-ps, 23-microJ pulses. Employing this source with a periodically poled lithium niobate crystal in a traveling-wave geometry, we obtained extracavity frequency conversion with pump depletion of as much as 62% in the near infrared (1.46- 1.56 microm) with a pulse spectral width of 1.5nm and a beam quality M(2)=1.7.

Travelling-wave parametric conversion of microjoule pulses with LBO

Abstract We report on the travelling-wave parametric generation which employs a temperature-tuned LBO crystal pumped by a ≈ 1 ps dye-laser source. Pulses of good spatial quality, tunable from 0.8 to 2 μm, are obtained with pump pulses of a few microjoules. Temporally structured pump pulses allow for the lower thresholds and the shorter time durations.

Powerful sub-100-fs pulses broadly tunable in the visible from a blue-pumped parametric generator and amplifier

By combining a low-gain single-pass collinear amplifier with a high-gain noncollinear seeder, in which the group velocities are self-matched, we demonstrate highly efficient parametric conversion of frequency-doubled Ti:sapphire pulses of hundreds-microjoule energy. With β-barium borate in both seeder and amplifier, bandwidth-limited signal pulses tunable between 0.46 and 0.66 µm are obtained at a 1-kHz-repetition rate, with duration as short as 78 fs and energy as much as 17 µJ in the visible.

Compensation of the Group-Velocity Mismatch in a Blue-Pumped Non-Collinear Parametric Generator of Femtosecond Pulses

The recent development and spread of high-power femtosecond amplified solid-state laser systems has greatly stimulated the interest in Travelling-Wave Optical Parametric Generators1 as the most suitable means for achieving a very broad wavelength-tunability from such sources2, 3. In particular, the extension of the accessible spectrum to the visible-near UV range for 100 fs pulses seems very promising for spectroscopic applications4, 5.