Partially disordered Yb:Gd x Y 1-x VO 4 crystal for femtosecond lasers

Abstract

ABSTRACT The results of experimental spectroscopic and laser investig ations of ytterbium-doped partially (mixed) disordered tetragonal gadolinium-yttrium vanadate crystals at 5-300 K temperature range under laser diode pumping are presented and compared with yttrium vanadate crystals. The Yb:Gd x Y 1-x VO 4 (x=0.64) partially (mixed) disordered crystals demonstrate large stimulated emission cross-section compared with the values of Yb:YVO 4 crystals. Polarized absorption and fluorescence spectra in the 5-300 K temperature range are investigated and gain cross-sections are deduced at room and liquid nitrogen temperatures. The amplitudes of emission cross-sections are increased almost fourfold at liquid nitrogen temperature in comparison with the same at room temperature at wavelength near 1006 nm. The CW and ultrashort pulses generation with additional SESAM structure have been investigated in the folded resonator at 975 nm laser diode pumping at room temperature. At low temperature the estimations for different inversion population ratios show that duration of pulses are somewhat varied. Keywords: new active laser media, ytterbium ions, solid-state femtosecond laser systems