Milliradian precision ultrafast pulse control for spectral phase metrology

A pulse-shaper-based method for spectral phase measurement and compression with milliradian precision is proposed and tested experimentally. Measurements of chirp and third-order dispersion are performed and compared to theoretical predictions. The single-digit milliradian accuracy is benchmarked by a group velocity dispersion measurement of fused silica

Multi-millijoule, few-cycle 5 µm OPCPA at 1 kHz repetition rate

A table-top midwave-infrared optical parametric chirped pulse amplification (OPCPA) system generates few-cycle pulses with multi-10 GW peak power at a 1 kHz repetition rate. The all-optically synchronized system utilizes ZnGeP2 nonlinear crystals and a highly stable 2 µm picosecond pump laser based on Ho:YLiF4. An excellent energy extraction is achieved by reusing the pump pulse after the third parametric power amplification stage, resulting in 3.4 mJ idler pulses at a center wavelength of 4.9 µm. Pulses as short as 89.4 fs are achieved, close to only five optical cycles. Taking into account the pulse energy, a record high peak power of 33 GW for high-energy mid-IR OPCPAs beyond 4 µm wavelength is demonstrated. © 2020 OSA - The Optical Society. All rights reserved

Dispersion-engineered multi-pass cell for single-stage post-compression of an ytterbium laser

Post-compression methods for ultrafast laser pulses typically face challenging limitations, including saturation effects and temporal pulse breakup, when large compression factors and broad bandwidths are targeted. To overcome these limitations, we exploit direct dispersion control in a gas-filled multi-pass cell, enabling, for the first time to the best of our knowledge, single-stage post-compression of 150 fs pulses and up to 250 µJ pulse energy from an ytterbium (Yb) fiber laser down to sub-20 fs. Dispersion-engineered dielectric cavity mirrors are used to achieve nonlinear spectral broadening dominated by self-phase modulation over large compression factors and bandwidths at 98% throughput. Our method opens a route toward single-stage post-compression of Yb lasers into the few-cycle regime

A dispersion-engineered multi-pass cell for single-stage post compression of an Ytterbium laser

Post-compression methods for ultrafast laser pulses typically face challenging limitations including saturation effects and temporal pulse break-up when large compression factors and broad bandwidths are targeted. To overcome these limitations, we exploit direct dispersion control in a gas-filled multi-pass cell, enabling for the first time single-stage post-compression of 150 fs pulses and up to 250 uJ pulse energy from an Ytterbium (Yb) fiber laser down to sub-20 fs. Dispersion-engineered dielectric cavity mirrors are used to achieve nonlinear spectral broadening dominated by self-phase-modulation over large compression factors and bandwidths at 98% throughput. Our method opens a route towards single-stage post-compression of Yb lasers into the few-cycle regime

Measurement of Pulse Train Instability in Ultrashort Pulse Characterization

Die Messung ultrakurzer Laserpulse ist ein Eckpfeiler der ultraschnellen Laserphysik, da die Gültigkeit eines Experiments von der Glaubwürdigkeit seiner Messtechnik abhängt. Etablierte Puls-Charakterisierungstechniken beruhen jedoch häufig auf einer Mittelung über viele Pulse. Daher können sie falsche Informationen liefern, wenn die zeitliche Form von Puls zu Puls variiert. Diese Dissertation bietet Strategien zum sicheren Erfassen und Messen einer Degradierung der Puls-Kohärenz mit Hilfe von frequenzaufgelöstem optischem Gating (FROG), spektraler Phaseninterferometrie für die direkte Rekonstruktion elektrischer Felder (SPIDER) und Dispersionsscan (D-scan). Zu diesem Zweck werden Verbesserungen der Charakterisierungstechniken entwickelt. Die in dieser Arbeit entwickelten neuen Werkzeuge eröffnen nun einen Weg zur Untersuchung der Degradierung der Inter-Puls-Kohärenz, was eine zuverlässige Ultrakurzpulsmetrologie ermöglicht und das zuvor nicht nachweisbare Problem der Pulsfolgeninstabilität löst.The measurement of ultrashort laser pulses is a cornerstone of ultrafast laser physics, as the validity of any experiment depends on the credibility of its measurement technique. However, established pulse characterization techniques often rely on averaging over many pulses. Therefore, they can return incorrect information if the temporal shape varies from pulse to pulse. This thesis provides strategies to safely detect and measure interpulse coherence degradation, using frequency-resolved optical gating (FROG), spectral phase interferometry for direct electric-field reconstruction (SPIDER), and dispersion scan (d-scan). To this end, improvements of the characterization techniques themselves are devised. The set of new tools developed in this thesis now opens up an avenue for the investigation of interpulse coherence degradation, leading to a more reliable ultrashort pulse metrology and solving the previously undetectable problem of pulse train instability