Low-threshold diode-pumped Yb3+, Na+: CaF2 self-Q-switched laser

For the first time to our knowledge, the laser performance of Yb3+, Na+-codoped CaF2 single crystals was demonstrated. Self-Q-switched laser operation at 1050nm was observed for 976 nm diode pumping at room temperature. On 5 W of incident power, the repetition rate and width of the self-Q-switched pulses reached 28 kHz and 1.5 mu s, respectively. A maximal slope efficiency of 20.3% and minimal threshold absorbed pump power of 30 mW were respectively achieved with different output couplers, showing the promising application of Yb3+, Na+-codoped CaF2 crystals as compact and efficient solid-state lasers. (C) 2005 Optical Society of America.

Codoping Na+ to modulate the spectroscopy and photoluminescence properties of Yb3+ in CaF2 laser crystal

kinds of Yb3+- and Na+-codoped CaF2 laser crystal with different Na:Yb ratios of 0, 1.5, and 10 are grown by the temperature gradient technique. Room-temperature absorption, photoluminescence spectra, and fluorescence lifetimes belonging to the transitions between ground state F-2(7/2) and excited state F-2(5/2) of Yb3+ ions in the three crystals are measured to study the effect of Na+. Experimental results show that codoping Na+ ions in different Na:Yb ratios can modulate the spectroscopy and photoluminescence properties of Yb3+ ions in a CaF2 lattice in a large scope. (c) 2005 Optical Society of America

Cooperative and charge transfer luminescence in Yb3+ -doped yttrium aluminum perovskite (YAlO3)

YAlO3 (YAP) crystals with different Yb3+ concentration have been grown by Czochralski method and cooperative fluorescence of Yb3+ ions in YAP crystal was studied under 940-nm infrared (IR) LD excitation at room temperature. The Yb concentration dependence of absorption intensity of IR and charge transfer bands exhibit different features. The green emission band in the region of 480-520nm was assigned to the cooperative deexcitation of two Yb3+ ions. The remaining upconverted emission bands containing various sharp peaks associated with impurity ions were observed and discussed. Charge transfer luminescence of heavily doped 20at% Yb:YAP is strongly temperature dependent and no concentration quenching of the charge transfer luminescence was found through the investigation of different Yb levels samples. (c) 2006 Elsevier B.V. All rights reserved.

Spectral properties and charge transfer luminescence of Yb3+ : Gd3Ga5O12 (Yb : GGG) crystal

The Yb (10%):GGG and Yb (30%): GGG crystals have been grown by the Czochralski method. The chemical compositions are: Yb1.07Gd1.74Ga5.19O12 and Yb0.33Gd1.47Ga5.2O12. The absorption and emission spectra of Yb:GGG crystal at room temperature have been measured. The spectroscopic parameters of Yb:GGG and Yb:YAG have been compared. Optical absorption spectra of Yb:GGG show 4f-4f transitions related to Gd3+ ion around 300 nm, and also an onset of charge transfer (CT) transitions from oxygen ligands to Gd3+ or Yb3+ cations below 240nm. The CT absorption of Yb3+ is largely overlapped by that of Gd3+ ions. (c) 2005 Elsevier B.V. All rights reserved.