arXiv subjects

Kilian Fritsch

Publications and source records attributed to Kilian Fritsch.

7 recordsLinked to original sources

arXiv2025

Supercontinuum Generation in the Low-Peak-Power Regime Using a Single-Stage Multipass Cell

We demonstrate a single-stage multipass cell (MPC) compressor driven directly by a 500 nJ, 5 W, 120 fs, 10 MHz oscillator that delivers efficient spectral broadening from 800 to 1200 nm with >75% transmission. The compressed pulses approach the Fourier limit (FTL) of 8.1 fs, representing, to the best of our knowledge, the first realization of supercontinuum (SC) generation and compression in a single-stage MPC at such low, MW-level, input peak power. This compact, high-repetition-rate source holds strong potential for multiphoton microscopy and coherent Raman imaging.

physics.optics↗

arXiv2024

Amplification-free GW-level, 150 W, 14 MHz, and 8 fs, thin-disk laser oscillator

We report an amplification-free thin-disk laser oscillatory system delivering 0.9 GW peak power. The 120 fs pulses at 14 MHz containing 12.8 $μ$J delivered by thin-disk oscillator were compressed by factor 15 down to 8.0 fs with 148 W average output power and 82 % overall efficiency. Additionally, we showed that even a sub-two-cycle operation with 6.2 fs can be reached with this technology. The system will be a crucial part of the XUV frequency comb being developed and a unique high-repetition rate driver for attosecond pulse generation.

physics.optics↗

arXiv2022

Spectral broadening in convex-concave multipass cells

Since its first demonstration in 2016, the multi-pass spectral broadening technique has covered impressive ranges of pulse energy (3 $μ$J - 100 mJ) and peak power (4 MW - 100 GW). Energy scaling of this technique into the joule-level is currently limited by phenomena such as optical damage, gas ionization and spatio-spectral beam inhomogeneity. These limitations can be overcome by the novel multi-pass convex-concave arrangement, which exhibits crucial properties such as large mode size and compactness. In a proof-of-principle experiment, 260 fs, 15 $μ$J and 200 $μ$J pulses are broadened and subsequently compressed to approximately 50 fs with 90 % efficiency and excellent spatio-spectral homogeneity across the beam profile.

physics.optics↗

arXiv2022

White Light Generation and Few Cycle Pulse Compression in Cascaded Multipass Cells

We report supercontinuum generation and pulse compression in two stacked multipass cells based on dielectric mirrors. The 230 fs pulses at 1 MHz containing 12 $μ$J were compressed by factor 33 down to 7 fs, corresponding to 1.0 GW peak power and overall transmission of 84 %. The source is particularly interesting for such applications as time-resolved ARPES, photoemission electron microscopy, and nonlinear spectroscopy.

physics.optics↗

arXiv2022

Free-space quasi-phase matching

We report a new approach to phase matching of nonlinear materials based on the free space multipass cells. This concept quasi-phase matches crystalline quartz and increases the second harmonic generation efficiency by a factor 40.

physics.optics↗

arXiv2022

110 MW Thin-Disk Oscillator

A compact Kerr-lens mode-locked thin-disk oscillator delivering 110 MW output peak power, the highest among all oscillators, is reported. A pulse train with a repetition rate of 14 MHz carries 115 fs long, 14.4 uJ pulses resulting in 202 W of average power. This compact, simple, and stable oscillator is a suitable driver and an important milestone for further high harmonics generation and the development of extreme ultraviolet transportable frequency comb sources.

physics.optics↗

arXiv2020

Dual-comb thin-disk oscillator

For the first time to our knowledge, a dual-comb laser based on thin-disk technology and its application to direct frequency comb spectroscopy are presented. The peak power (0.6 MW) and the average power (12 W) of our Yb:YAG thin-disk dual-comb system are more than one-order-of-magnitude higher than in any previous systems. The scheme allows easy adjustment of the repetition frequency difference during operation. A time-domain signal recorded over 10 μs without any active stabilization was sufficient to resolve individual comb lines after Fourier transformation. The demonstration should enable a wider adoption of dual-comb systems towards practical applications in research laboratories. Its simplicity and compactness especially for the realization of tri- and multi-comb systems and conversion into the still poorly covered UV and VUV ranges makes it a promising next-generation technology.

physics.optics↗