2 research outputs found
Measurement of 10 fs pulses across the entire Visible to Near-Infrared Spectral Range
Tuneable ultrafast laser pulses are a powerful tool for measuring
difficult-to-access degrees of freedom in materials science. In general these
experiments require the ability to address resonances and excitations both
above and below the bandgap of materials, and to probe their response at the
timescale of the fastest non-trivial internal dynamics. This drives the need
for ultrafast sources capable of delivering 10-15 fs duration pulses tuneable
across the entire visible (VIS) and near infrared (NIR) range, 500 nm - 3000
nm, as well as the characterization of these sources. Here we present a single
frequency-resolved optical gating (FROG) system capable of self-referenced
characterization of pulses with 10 fs duration across the entire VIS-NIR
spectral range. Our system does not require auxiliary beams and only minor
reconfiguration for different wavelengths. We demonstrate the system with
measurements of pulses across the entire tuning range
Investigation of spatiotemporal output beam profile instabilities from differentially pumped capillaries
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