Philip Schlup

Phase-preserving chirped-pulse optical parametric amplification to 17.3 fs directly from a Ti:sapphire oscillator.

Phase-stabilized 12-fs, 1-nJ pulses from a commercial Ti:sapphire oscillator are directly amplified in a chirped-pulse optical parametric amplifier and recompressed to yield near-transform-limited 17.3-fs pulses. The amplification process is demonstrated to be phase preserving and leads to 85-microJ, carrier-envelope-offset phase-locked pulses at 1 kHz for 0.9 mJ of pump, corresponding to a single-pass gain of 8.5 x 10(4).

Ultra-broadband chirped-pulse optical parametric amplifier with angularly dispersed beams

We propose a BBO-based chirped-pulse optical parametric amplifier employing an angularly dispersed signal beam to yield a full-octave gain bandwidth, sufficient for the direct amplification of sub-10-fs pulses. Numerical simulations show that this power-scalable amplifier configuration has a small-signal gain of 10(7) at a pumping intensity of 45 GW/cm(2). The additional phase-matching flexibility compared to alternative configurations permits the suppression of parasitic second harmonic generation of the signal beam.

5.1 fs pulses generated by filamentation and carrier envelope phase stability analysis

Intense 5.1 fs CEO (carrier envelope offset) phase stable pulses were generated through two-fold filamentation in a noble gas at atmospheric pressure. The preservation of the CEO phase during the filamentation process was investigated. We show that generating these short pulses using filaments is not detrimental for the CEO phase stabilization, and that the more than one octave-spanning spectrum intrinsically generated by the process is feasible, and offers certain benefits, for direct use in single shot f–2f spectral interferometry.

Enhanced VUV-assisted high harmonic generation

We have enhanced extreme ultraviolet (XUV) harmonics around 90 eV in He using a combination of vacuum ultraviolet harmonics, generated in a Xe capillary, and the strong infrared (IR) laser pulse. With no changes in the IR input energy or the configuration of the He target, the collinearly focused combination of the two fields changed the spectral properties and increased the yield of the XUV harmonics compared to those generated with the IR field alone.

Control of high-order harmonic emission using attosecond pulse trains

We show that attosecond pulse trains are a natural tool to control strong field processes such as high-order harmonic generation. Coherently combining an attosecond pulse train with an IR driving field, we predict and experimentally confirm enhancement and spectral narrowing of the harmonic yield at photon energies around 90 eV. The use of an attosecond pulse train to seed the harmonic generation process replaces tunneling ionization with a single-photon ionization step, therefore permitting the manipulation of the time–frequency properties of high-order harmonic generation already at the single-atom level.

Frequency-sheared, time-delayed extreme-ultraviolet pulses produced by high-harmonic generation in argon

We report the production of frequency-sheared high harmonics in argon by control of the envelope and chirp of the electric field of the femtosecond driving laser pulse. Using the classic three-step model of high-harmonic generation, we established a direct link between the properties of the harmonics and the fully characterized driving pulses. A simulation of the single-atom response in the strong-field approximation confirms the simple picture and shows good agreement with the experimental results.

Ionization of ar with circularly polarized 5.5-fs pulses for the determination of CEO phase

The ionization rate of Ar with circularly polarized ultrashort laser pulses shows a spatial dependence attributable to the carrier-envelope phase of the pulse. A numerical simulation shows similar characteristics.

Intense CEO phase stabilized ultra-short pulses approaching the single cycle limit

Intense 5.1-fs pulses were generated through filamentation in argon while maintaining the CEO phase. The benefits to CEO phase control of using the generated octave-spanning spectrum for single shot f-2f spectral interferometry are also presented.

Intense 5.1-fs Carrier-Envelope-Phase Controlled Pulse Generation through Filamentation

Intense 5.1-fs pulses were generated through filamentation in argon. The CEO (carrier envelope offset) phase control is investigated of using the intense, octave-spanning spectrum generated during this process, directly for single shot f-2f spectral interferometry.

Determination of the CEO Phase — ionization of He with Circularly polarized 5.5-fs Pulses

The intensity distribution in momentum space of He, ionized with circularly polarized ultrashort laser pulses, shows a clear dependence on the carrier-envelope phase of the pulse. A numerical simulation reproduces the characteristics found in the experiment.