No abstract

Passive mode locking of a continuous wave diodepumped Tm:KYW laser at 1.94 μm was demonstrated by using glass doped with PbS quantum dots as a saturable absorber. The laser operated in Q-switched mode-locking regime. Conversion efficiency of free-running output power to output power of pulsed operation was estimated at 30%.Intensity, a.u.

The thermal lensing effect was characterized in the diode-pumped monoclinic N g -cut Tm:KYW crystal under laser operation conditions at the wavelength of 1.94 µm. The thermal lens was found to be slightly astigmatic; its optical power D being positive for rays lying in all meridional planes. Thermal lens sensitivity factors M = dD/dP abs equal 11.8 m −1 /W and 8.8 m −1 /W (with respect to the absorbed pump power P abs ) for principal meridional planes containing N p and N m axes. Nearly athermal behavior of N g -cut crystal is associated with the mutual compensation of different impacts to the thermal lens optical power that arise from temperature dependence of the refractive index dn/dT and anisotropic thermal expansion. It was utilized to produce passively cooled diode-pumped 0.65 W cw Tm:KYW microchip laser with slope efficiency of 44 % and low thermo-optic aberrations.

We demonstrate a compact extreme ultraviolet (XUV) source based on high-harmonic generation (HHG) driven directly inside the cavity of a mode-locked thin-disk laser oscillator. The laser is directly diode-pumped at a power of only 51 W and operates at a wavelength of 1034 nm and a 17.35 MHz repetition rate. We drive HHG in a high-pressure xenon gas jet with an intracavity peak intensity of 2.8×10 W/cm and 320 W of intracavity average power. Despite the high-pressure gas jet, the laser operates at high stability. We detect harmonics up to the 17th order (60.8 nm, 20.4 eV) and estimate a flux of 2.6×10 photons/s for the 11th harmonic (94 nm, 13.2 eV). Due to the power scalability of the thin-disk concept, this class of compact XUV sources has the potential to become a versatile tool for areas such as attosecond science, XUV spectroscopy, and high-resolution imaging.

We demonstrate the first Kerr lens mode-locked Yb:CaGdAlO (Yb:CALGO) thin-disk laser oscillator. It generates pulses with a duration of 30 fs at a central wavelength of 1048 nm and a repetition rate of 124 MHz. The laser emits the shortest pulses generated by a thin-disk laser oscillator, equal to the shortest pulse duration obtained by Yb-doped bulk oscillators. The average output power is currently limited to 150 mW by the low gain and limited disk quality. We expect that more suitable Yb:CALGO disks will enable substantially higher power levels with similar pulse durations.