Doping Concentration Of Yb3 Research Articles

Energy transfer and sensitization blue-upconversion in Tm3+ /Yb3+ co-doped tellurite glasses

This paper reports on energy transfer and infrared-to-blue upconversion of Tm3+/Yb3+co-doped tellurite glasses upon excitation with 800 and 980 nm laser diode (LD). The glasses were prepared by the conventional melting method. Their optical spectroscopic properties, direct and indirect sensitization upconversion have been discussed. An intense 475 nm blue upconversion was clearly observed upon excitation of a 980 nm LD. It is interesting to note that the peaks of the blue upconversion at 475 nm changed first to 452 nm, then to 468 nm with increasing Yb-doping concentration upon excitation of a 800 nm LD, which might be due to the indirect sensitization upconversion. To our knowledge, a similar result has not been reported before. The mechanism involved has been explained.

Q-Switched Large-Mode-Area Yb-Doped Fibre Laser Using GaAs asSaturable Absorber

A passive Q-switched large-mode-area Yb-doped fibre laser isdemonstrated using a GaAs wafer as the saturable absorber. A high Ybdoping concentration double-clad fibre with a core diameter of 30 μmand a numerical aperture of 0.07 is used to increase the laser gainvolume, permitting greater energy storage and higher output power thanconventional fibres. The maximum average output power is 7.2 W at1080 nm wavelength, with the shortest pulse duration of 580 ns and thehighest peak power of 161 W when the laser is pumped with a 25 W diodelaser operating at 976 nm. The repetition rate increases with the pumppower linearly and the highest repetition rate of 77 kHz is obtainedin the experiment.

Comparison of fluorescence spectra of Yb:Y3Al5O12 and Yb:YAlO3 single crystals

Yb:Y3Al5O12 (Yb:YAG) single crystals with Yb doping concentration 0.5at.%, 5at.%, 15at.%, 25at.%, 50at.%, 100at.% and Yb:YAlO3 (Yb:YAP) single crystals with Yb doping concentration 0.5at.%, 5at.%, 15at.%, 30at.% were grown by the Czochralski process. The fluorescence spectra of these crystals and the effects of self-absorption on the shape of the fluorescence spectra were studied. Through comparing the fluorescence spectra of Yb:YAG and Yb:YAP, all results indicate that the effects of self-absorption on the fluorescence spectra of Yb:YAP are remarkably stronger than that of Yb:YAG at the same Yb concentration.

Effects of Yb concentration on the fluorescence spectra of Yb-doped YAlO 3 single crystals

0.5 at.% Yb:YAlO 3(YAP), 5 at.% Yb:YAP and 15 at.% Yb:YAP were grown using the Czochralski method. Their absorption and fluorescence spectra were measured at room temperature and their emission line shape was calculated using the method of reciprocity. It was observed that the fluorescence spectra changed appreciably with the increasing of Yb concentration. For 0.5 at.% Yb:YAP, the line shape of fluorescence is very similar with the calculated emission line shape; with the increasing of Yb doping concentration, the line shape of fluorescence is very different from the calculated emission line shape. These phenomena are caused by the strong self-absorption at 979 and 999 nm for Yb:YAP.

Preparation and upconversion emission of nanocrystalline ZrO2:Er3+-Yb3+

Er3+, Yb3+ codoped ZrO2 nanocrystalline powders were prepared by chemical co-precipitation. We determined the crystal structures and the room temperature upconversion emission properties of samples with different doping concentrations of Yb3+ and at different sintering temperatures, respectively. It is shown that the monoclinic phase increases with the sintering temperature and the tetragonal phase increases with the increasing of Yb3+ concentration. We found that the green emission intensity and the red emission intensity of the samples sintered at 800℃ were enhanced with the increasing of Yb3+ concentration, but the red emission intensity increased much more. The quadratic dependence of the green and the red emissions on excitation power indicates that a two-photon absorption process occurs under 976nm excitation. The infrared emission properties were also discussed in the present paper.

Effects of Yb concentration on the spectroscopic properties of Yb: Y3Al5O12

Yb:YAG single crystals with Yb doping concentration 5.4, 16.3, 27.1, 53.6, and 100at.% were grown by the Czochralski process. The effects of Yb concentration on the absorption spectra (190–1100nm), fluorescence spectra under 940nm and X-ray excitation were studied. The concentration quenching of fluorescence was observed when the Yb doping concentration reaches to as high as 27.1at.% for Yb:YAG. Under 940nm excitation, the influence of the self-absorption at 969 and 1029nm on the fluorescence spectra is not evident when the Yb doping concentration is as high as 27.1at.%. However, it can greatly change the shape of fluorescence spectra of Yb:YAG when the Yb doping concentration reaches to above 53.6at.%.

Fabrication of highly ytterbium (Yb 3+)-doped YAG thin film by pulsed laser deposition

As an infrared laser waveguide, the epitaxial growth of 5 μm -thick ytterbium (Yb 3+)-doped yttrium aluminum garnet (YAG) thin films on YAG(1 1 1) (Y 3Al 5O 12) substrate has been demonstrated by pulsed KrF laser deposition with post-annealing. Highly Yb 3+-doped (up to 100 at.%) YAG films have been epitaxially grown on YAG(1 1 1). The crystalline quality of the grown films does not degrade even with high doping concentrations of Yb 3+ ions up to 100 at.%. The roughness (root mean square) of the film is measured as 1.27 nm without droplets or particulates. The optical properties of these films have been characterized in terms of absorption spectra, fluorescence spectra and fluorescent lifetime. The refractive index of n at 1.03 μ m is measured to be 1.851±0.0141 for 50 at.% Yb 3+:YAG. An emission lifetime of 0.90±0.01 ms is obtained for 1.03 μ m transition.