Electromagnetic and gravitational radiation of blazar OJ 287.

Based on long-term monitoring data of the blazar, a new model for determining the parameters of this close binary supermassive black hole (SMBH) is proposed. The model uses the laws of celestial mechanics and results of harmonic analysis of observational data obtained mainly in the radio and optical wavelength ranges. Within the framework of the proposed model, the masses of SMBH companions, the values of their orbital elements, the parameters of the accretion disk, and its dimensions and thickness were determined.

High-power Yb:YAG thin-disk laser with 80% efficiency pumped at the zero-phonon line.

We report a 3-kW thin-disk laser with 80% optical efficiency employing zero-phonon line pumping at 970 nm. A detailed comparison to conventional pumping at 940 nm is provided, which shows almost twice the pump power density handling capability.

Diode pumped solid state kilohertz disk laser system for time-resolved combustion diagnostics under microgravity at the drop tower Bremen.

We describe a specially designed diode pumped solid state laser system based on the disk laser architecture for combustion diagnostics under microgravity (μg) conditions at the drop tower in Bremen. The two-stage oscillator-amplifier-system provides an excellent beam profile (TEM00) at narrowband operation (Δλ < 1 pm) and is tunable from 1018 nm to 1052 nm. The laser repetition rate of up to 4 kHz at pulse durations of 10 ns enables the tracking of processes on a millisecond time scale.

High-repetition-rate regenerative thin-disk amplifier with 116 microJ pulse energy and 250 fs pulse duration.

A thin-disk regenerative amplifier based on Yb-doped potassium yttrium tungstate is operated at 40 kHz with an output pulse energy of 116 microJ and a pulse duration of 250 fs. Dispersive stretching of the pulse during amplification instead of an external stretcher is used to avoid high peak intensities. The small amount of the laser active material in the amplifier inherent for the thin-disk laser design and a large beam radius in the Pockels cell reduce nonlinear effects further.