Особенности одновременной генерации низко- и высокодобротных мод в гетеролазерах на квантовых точках с большим временем некогерентной релаксации оптических дипольных колебаний

We investigate the features of multimode steady-state generation of the superradiant heterolasers which have an active medium formed by the quantum dots with long incoherent relaxation time and a cavity of a combined Fabry-Perot type with a distributed feedback of the counter-propagating waves. We show that a quantum-coherent dynamics of the optical dipole oscillations and a population inversion of the working levels in an ensemble of the quantum dots with a strong inhomogeneous broadening of a spectral line may lead to a simultaneous lasing of modes with a various degree of phasing and/or correlation and with qualitatively different dynamical behavior, including quasi-stationary, metastable, self-modulated, pulsed-periodic, quasi-chaotic ones.

Free-electron laser multiplex driven by a superconducting linear accelerator

Free-electron lasers (FELs) generate femtosecond XUV and X-ray pulses at peak powers in the gigawatt range. The FEL user facility FLASH at DESY (Hamburg, Germany) is driven by a superconducting linear accelerator with up to 8000 pulses per second. Since 2014, two parallel undulator beamlines, FLASH1 and FLASH2, have been in operation. In addition to the main undulator, the FLASH1 beamline is equipped with an undulator section, sFLASH, dedicated to research and development of fully coherent extreme ultraviolet photon pulses using external seed lasers. In this contribution, the first simultaneous lasing of the three FELs at 13.4 nm, 20 nm and 38.8 nm is presented.