Jason Tackett

Carrier-envelope phase stabilized 5.6fs, 1.2mJ pulses

The authors report the generation of 1.2mJ pulses with a duration of 5.6fs from a neon filled hollow-core fiber seeded with carrier-envelope phase stabilized 2.2mJ, 25fs pulses. The carrier-envelope phase after the fiber was measured by a second, out-loop f-to-2f interferometer. With seed pulse power locked, the carrier-envelope phase of the two-cycle pulses is controlled to a standard deviation of 370mrad. The peak power of the carrier-envelope phase stabilized pulses, 0.2TW, is twice that previously generated. The significance of seed pulse energy stability for carrier-envelope phase stabilization of few-cycle laser pulses is demonstrated.

Determining the phase-energy coupling coefficient in carrier-envelope phase measurements

By using two f-to-2f interferometers, we measured the phase-energy coupling coefficient for the first time. The results reveal that a 1% in-loop laser energy change causes a 160 mrad carrier-envelope phase shift to output pulses.

Reduction of fast carrier-envelope phase jitter in femtosecond laser amplifiers.

The phase noise of the f-to-2f interferometer used for stabilizing the carrier-envelope phase of a femtosecond laser oscillator was studied by adding a He-Ne laser beam co-propagating with the short pulse laser beam. The noise was reduced to ~60 mrad by stabilizing the optical path length difference of the interferometer. This suppressed the fast jitter of the carrier-envelope phase of the amplified laser pulses from 79 to 48 mrad.

Mechanism of phase-energy coupling in f-to-2f interferometry.

White-light generation has been used widely in single-shot f-to-2f interferometers for stabilizing the carrier-envelope (CE) phase of laser amplifiers. The accuracy of the relative phase values measured by such an interferometer is affected by fluctuations in the laser pulse energy. A simple two-step model is proposed to explain the mechanism that couples the laser energy and the CE phase. The model explains the experimentally observed dependence of the group delay between the f and the 2f pulses on the laser energy, as well as the CE phase shift caused by the pulse energy variation.

Carrier envelope phase effects on polarization gated attosecond spectra

Polarization gated high harmonic generation in argon gas was phase matched to produce a single or double pulses with 104 photons. It was accomplished by optimizing the argon gas pressure. The spectrum interference of the two pulses is affected by the carrier-envelope phase like in Youngs experiments. The XUV flux is sufficient for measuring the single shot XUV spectrum in the 33eV-55eV photon energy range. The spectral profile was a super-continuum for some shots and showed discrete high harmonics peaks for other shots. The carrier-envelope phase of pulses from grating-based chirped pulse amplification was also varied smoothly to cover a 2π range by controlling the grating separation. It is demonstrated that XUV spectra measures both the absolute value of the phase and the stability of the phase by measuring the phase with an f-to-2f setup and by the variation of XUV spectra from polarization gated high harmonics generation.

Carrier-envelope phase stabilized 5.6 fs, 1.2 mJ pulses

Carrier-envelope phase stabilized 1.2 mJ pulses with duration of 5.6 fs were obtained from a Ne filled hollow-core fiber. With power locking the phase is controlled to 370 mrad measured by out-loop f-to-2f interferometery.

Laser power locking for improvement of carrier-envelope phase stability

The pulse energy fluctuation of a kilohertz femtosecond laser was reduced from 1.33% RMS to 0.28% RMS, which improves the carrier-envelope phase stability from 500 mrad to 200 mrad.

Reducing the fast carrier-envelope phase jitter of amplified femtosecond laser pulses

Stabilizing the interference signal obtained from co-propagating a HeNe beam in the f- to-2f interferometer used for carrier-envelope phase stabilization of a femtosecond laser oscillator reduced the fast phase jitter of the amplified pulses by ~40%.

Attosecond two-slit interference controlled by carrier-envelope phase

High harmonics generation was polarization gated with few-cycle laser pulses to produce two attosecond pulses with 104 XUV photons. The spectrum interference of the two pulses is affected by the carrier-envelope phase like in Young¿s experiments.

Determining Phase-Energy Coupling Coefficient in Carrier-envelope Phase Measurements

By using two f-to-2f interferometers, we measured the phase-energy coupling coefficient for the first time. The results reveal that a 1% in-loop laser energy change causes a 160 mrad carrier-envelope phase shift to output pulses.