Showing papers by "Uwe Griebner published in 2000"
TL;DR: Evidence is presented that strong space-time coupling results in a time-dependent interference zone and significant changes of contrast, envelope function, and spatial frequency spectrum in comparison with continuous wave data.
Abstract: Multiple quasi-Bessel beams are generated by transmission of sub-30-fs pulses from a Ti:sapphire laser through refractive thin-film microaxicon arrays. Time-integrated intensity distributions at several axial positions and for pulse durations of 26 and 12.5 fs reveal significant changes of contrast, envelope function, and spatial frequency spectrum in comparison with continuous wave data. Evidence is presented that strong space-time coupling results in a time-dependent interference zone.
67 citations
TL;DR: In this article, a high-gain diode-pumped ytterbium-doped fiber-amplifier system was proposed for femtosecond seed-laser pulses.
Abstract: We report on a high-gain diode-pumped ytterbium-doped fiber-amplifier system delivering pulse energies in the 100-μJ range at high repetition rates (32 kHz) with nearly-diffraction-limited beam quality (M2∼1.7) at a 1060-nm center wavelength. Femtosecond seed-laser pulses are stretched in a commercially available single-mode fiber and compressed after amplification to subpicosecond pulse duration. In a multimode Yb-doped fiber amplifier we have demonstrated average powers of up to 22 W and single-pulse energies of up to 130 μJ.
28 citations
TL;DR: In this paper, a short diffusion-bonded diode-pumped Yb:YAG rectangular channel waveguide of 100 μm cross section was used to achieve high overlap of the pump mode and the nonguided resonator mode.
Abstract: We report the laser performance of a short diffusion-bonded diode-pumped Yb:YAG rectangular channel waveguide of 100 μm cross section. Using an end-pumped configuration guiding only the slow axis, a high overlap of the pump mode and the nonguided resonator mode is achieved. With 4 W of pump power from two 60 μm high-power broad-stripe diodes, 0.7 W of output power with nearly diffraction-limited performance is obtained.
10 citations
07 May 2000
TL;DR: In this article, a 5mm-long cladding-pumped planar waveguide with high asymmetrical gain profiles is presented. But, due to their small confocal parameters, the efficiency of direct end-pumping of extended active bulk media (length > 3 mm) with broad-stripe diode lasers is limited due to the overlap of pump and resonator mode over the entire length.
Abstract: Summary form only given.Diffusion-bonded planar waveguide geometries are very attractive for highly efficient diode pumped lasers. These waveguides are diode-pumped, in general in the waveguide plane, resulting in high asymmetrical gain profiles. The efficiency of direct end-pumping of extended active bulk media (length >3 mm) with broad-stripe diode lasers is limited due to their small confocal parameters and hence the overlap of pump and resonator mode over the entire length cannot be maintained. The advantages of cladding-pumped fiber lasers are well-known. Laser performance of a 5-mm long cladding-pumped 100-/spl mu/m Yb:YAG planar waveguide is reported. This configuration offers an excellent confinement of the pump field achieved by waveguiding of the slow-axis of the diode pump perpendicular to the active layer and non-guiding of the fast-axis.
13 Feb 2000
TL;DR: In this article, a modified cladding pump scheme for planar waveguides was proposed for the optimization of diode-pumped waveguide, stable, compact and mode-selective resonator-and gain structures.
Abstract: Rare-earth-doped diffusion bonded planar crystal waveguides have the potential to yield efficient, diode-pumped lasers and amplifiers. For the optimization of diode-pumped waveguides, stable, compact and mode-selective resonator- and gain structures are essential. For this purpose, we used a new modified cladding pump scheme for planar waveguides.