Timing and energy stability of resonant dispersive wave emission in gas-filled hollow-core waveguides

TL;DR

This study numerically analyzes the energy and timing stability of ultrashort pulses generated via resonant dispersive wave emission in gas-filled hollow-core waveguides, highlighting conditions for minimal noise and stability.

Contribution

It reveals how pump energy fluctuations affect pulse stability and identifies conditions where generated pulses are less noisy and highly stable despite pump instability.

Findings

Resonant dispersive wave emission can produce stable, few-femtosecond pulses.

Pump energy fluctuations are amplified at low energies but reduced at saturation.

Arrival-time jitter remains below one femtosecond under typical noise conditions.

Abstract

We numerically investigate the energy and arrival-time noise of ultrashort laser pulses produced via resonant dispersive wave emission in gas-filled hollow-core waveguides under the influence of pump-laser instability. We find that for low pump energy, fluctuations in the pump energy are strongly amplified. However, when the generation process is saturated, the energy of the resonant dispersive wave can be significantly less noisy than that of the pump pulse. This holds for a variety of generation conditions and while still producing few-femtosecond pulses. We further find that the arrival-time jitter of the generated pulse remains well below one femtosecond even for a conservative estimate of the pump pulse energy noise, and that photoionisation and plasma dynamics can lead to exceptional stability for some generation conditions. By applying our analysis to a scaled-down system, we demonstrate that our results hold for frequency conversion schemes based on both small-core microstructured fibre and large-core hollow capillary fibre.