W. Rudolph | Searcharxiv

arXiv2018

Mid IR hollow core fiber gas laser emitting at 4.6 um

Emission at 4.6 um was observed from an N2O filled hollow core fiber laser. 8-ns pump pulses at 1.517 um excited a vibrational overtone resulting in lasing on an R and P branch fundamental transition from the upper pump state. At optimum gas pressure of 80 Torr a photon conversion efficiency of 9% and a slope efficiency of 3% was observed from a mirrorless laser. The laser threshold occurred at an absorbed pump energy of 150 nJ in a 45-cm long fiber with 85 μm core diameter. The observed dependence of the laser output on gas pressure is shown to be a result of line broadening and relaxation rates.

physics.optics↗

arXiv2000

Automodulations in Kerr-lens Modelocked Solid-State Lasers

Nonstationary pulse regimes associated with self modulation of a Kerr-lens modelocked Ti:sapphire laser have been studied experimentally and theoretically. Such laser regimes occur at an intracavity group delay dispersion that is smaller or larger than what is required for stable modelocking and exhibit modulation in pulse amplitude and spectra at frequencies of several hundred kHz. Stabilization of such modulations, leading to an increase in the pulse peak power by a factor of ten, were accomplished by weakly modulating the pump laser with the self-modulation frequency. The main experimental observations can be explained with a round trip model of the fs laser taking into account gain saturation, Kerr lensing, and second- and third-order dispersion.

physics.optics↗