Low peak-power pulse compression in gas-filled Herriott cells in the 2 {\mu}m wavelength range

TL;DR

This paper presents an analytical method to optimize pulse compression in gas-filled Herriott cells at 2 μm wavelengths, demonstrating experimental pulse compression at low peak powers with durations around 40-55 fs.

Contribution

An analytical approach to maximize nonlinear phase shift in gas-filled Herriott cells, enabling efficient pulse compression at 2 μm with low peak powers.

Findings

Optimized Herriott cell configuration increases nonlinear phase shift.

Experimental pulse compression achieved at ~40 fs and ~55 fs durations.

Demonstrated pulse compression in both negative and positive dispersion regimes.

Abstract

At laser wavelengths longer than the prominent 1 {\mu}m range of high-power ytterbium-doped lasers, nonlinear phase shifts produced in nonlinear media for spectral broadening and subsequent pulse compression decrease drastically. Consequently, at the 2 {\mu}m wavelength range, the threshold of the applicable peak power for pulse compression in gas-filled multipass cells increases. The common approach of choosing a Herriott multipass cell configuration close to the concentric resonator does not necessarily lead to the highest total nonlinear phase shift, due to a restriction of the total number of reflections on the cell mirrors of a given size. Therefore, an analytical approach is presented here to maximize the nonlinear phase shift for a given set of mirrors, considering lossless and dispersionless propagation. Furthermore, to achieve pulse compression with gas-filled multipass cells for relatively low peak powers at wavelengths around 2 {\mu}m, we developed a high-pressure gas cell and demonstrated experimentally pulse compression in the negative- and positive dispersion regimes, with achieved pulse durations of around 40 fs and 55 fs respectively.