Green luminescence of Er3+ in stoichiometric KYb(WO4)2 single crystals

Abstract

We grew good-optical-quality KYb͑WO 4 ) 2 single crystals doped with erbium ions by the top seeded solution growth slow cooling method. Optical absorption of erbium was performed at room temperature ͑RT͒ and at 6 K. Green photoluminescence of erbium was achieved at RT and 6 K after selective excitation of ytterbium ions at 940 nm (10 638 cm Ϫ1 ). The splitting of all found excited energy levels and the ground energy level of erbium in KYb͑WO 4 ) 2 is presented derived from the accurate absorption and emission measurements, respectively. The lifetime of the Stokes and the anti-Stokes green emissions of erbium were measured after excitation at 488 nm (20 490 cm Ϫ1 ) and 940 nm(10 638 cm Ϫ1 ), respectively. We propose applying the up-conversion model to the observed green emission.

Sensitization ofEr3+emission at1.5μmbyMateos1, Pujol2, Güell3 et al. 2002Phys. Rev. BSelf Cite

“…These peaks are displaced in accordance with the difference in energy between the first and second sublevels of the excited 4 I 13/2 (⌬Eϭ28 cm Ϫ1 , see Table III͒. From this, we know the energy position of the energy sublevels of 23 We found all of these values in a previous study also of an erbium doped KYbW crystal, by analyzing the green emission channels, 24 where the transition was 4 S 3/2 → 4 I 15/2 . By doing this we also found the splitting of the ground level of erbium, which was very close to the one we found in this study, where the infrared transition was 4 I 13/2 → 4 I 15/2 .…”

Near-infrared photoluminescence from Ho3+-doped monoclinic KLu(WO4)2 crystal codoped with Tm3+

“…This spectroscopic process is very important in solidstate systems because it enhances the luminescence emission from the acceptor ion. Such a phenomenon has been observed in many crystals doped even with other ions, for example Er-Yb, Pr-Yb, Tm-Yb, etc [7].…”

Ultraviolet and visible emissions of Er3+ in monoclinic KYb(WO4)2 single crystals

“…21 220 cm −1 peak, 27 735 cm −1 ( 2 K 15/2 ) and 6603 cm −1 ( 4 I 13/2 ) that generated the 21 133 cm −1 peak (which coincided with that of thulium and makes that the relative intensity increased significantly). Other signals can be corroborated by the difference in energy between the Stark levels of erbium in KYbW [12]. Fig.…”

“…From the energy positions of the 4 S 3/2 sublevels (18 308 cm −1 and 18 376 cm −1 ; see ref. [12]), and by adding the abovementioned energy values of the emission signals, we found the energy position of the Starks levels of the 2 P 3/2 level. These values were 31 334 cm −1 and 31 360 cm −1 , which were reasonably around the energy position of the 2 P 3/2 level of erbium in other hosts [15].…”

“…We also doped KYbW crystals with Er 3+ ions at several dopant concentrations to characterize the potential laser transitions. Crystal growth data and optical characterization of the visible green and infrared 1.5 m emissions of erbium in KYbW:Er have been published in [11,12]. The most important features of the KYbW host doped with Er 3+ are, firstly, that the high quantity of Yb 3+ ions also with the very large absorption cross-section can efficiently transfer the pump energy to Er 3+ thus increasing the emission intensity in the UV-vis region, secondly, that due to the similar nature of the ions, concerning charge and size, it makes possible easy substitution in the host without introducing high changes in the crystal quality, and finally, that the transitions (absorption and emission) cross-sections in such tungstates are very large, so that the requirements of the pump beam quality is reduced, favoring the pump with diodes.…”