Investigation of spatiotemporal output beam profile instabilities from differentially pumped capillaries

Abstract

Differentially pumped capillaries, i.e., capillaries operated in a pressure gradient environment, are widely used for nonlinear pulse compression. In this work, we show that strong pressure gradients and high gas throughputs can cause spatiotemporal instabilities of the output beam profile. The instabilities occur with a sudden onset as the flow evolves from laminar to turbulent. Based on the experimental and numerical results, we derive guidelines to predict the onset of those instabilities and discuss possible applications in the context of nonlinear flow dynamics.

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• Generation of micro-J pulses in the deep UV at MHz repetition rates
• 23 mJ high-power fiber CPA system using electro-optically controlled divided-pulse amplification
• Generation of above-TW 1.5-cycle visible pulses at 1 kHz by post-compression in a hollow fiber