Seminars Archive

OP(CP)A-based pulse synthesis and its applications in attosecond science

Rossi, Giulio Maria
CFEL at DESY, Hamburg

Abstract
The coherent synthesis of ultrashort pulses generated via optical parametric (chirped-pulse) amplification (OP(CP)A) opened a path to tailor the electric field waveform of intense optical pulses with unprecedented freedom, enabling at the same time non-sinusoidal shapes and sub-cycle FWHM pulse durations. Tailoring the optical waveform permits to gain additional control over strong-field processes, such as high-harmonic generation (HHG). This allowed us firstly to generate isolated pulses directly, i.e. without additional gating techniques, and secondly to control their central wavelength, bandwidth and duration. Recently we have also observed the possibility, via specific waveforms, of extending the HHG cut-off photon energy, which for example reaches ~400 eV in neon despite a central wavelength of ~1.4 μm. These advances open up important developments for attosecond science. For example, the use of sub-cycle pump pulses for multi-photon/strong-field excitation allows for as-pump/as-probe resolution in transient absorption experiments over a range of energies from 30 to >400 eV. In addition, sub-cycle waveform tailoring can find interesting applications in other strong-field techniques such as high-harmonic spectroscopy or laser-induced electron diffraction, as well as in the quantum control of photochemical reactions.