1.48 and 1.84 μm thulium emissions in monoclinic KGd(WO4)2 single crystals

Abstract

Two dimensional ferroelectric domain patterns in Yb3+ optically active LiNbO3 fabricated by direct electron beam writing Appl. Phys. Lett. 102, 042910 (2013) Remanent-polarization-induced enhancement of photoluminescence in Pr3+-doped lead-free ferroelectric (Bi0.5Na0.5)TiO3 ceramic Appl. Phys. Lett. 102, 042907 (2013) Optical identification of oxygen vacancy types in SnO2 nanocrystals Appl. Phys. Lett. 102, 031916 (2013) Non-rare earth white emission phosphor: Ti-doped MgAl2O4 Appl. Phys. Lett. 102, 031104 (2013) Photoluminescence properties of (Ce3+, Mn2+)-codoped CaCO3 red phosphor J. Appl. Phys. 113, 033519 (2013) Additional information on J. Appl. Phys. By exciting at 788 nm, we have characterized the near infrared emissions of trivalent thulium ions in monoclinic KGd(WO 4 ) 2 single crystals at 1.48 and 1.84 m as a function of dopant concentration from 0.1% to 10% and temperature from 10 K to room temperature. We used the reciprocity method to calculate the maximum emission cross-section of 3.0ϫ10 Ϫ20 cm 2 at 1.838 m for the polarization parallel to the N m principal optical direction. These results agrees well with the experimental data. Experimental decay times of the 3 H 4 → 3 F 4 and 3 F 4 → 3 H 6 transitions have been measured as a function of thulium concentration.

Efficient tunable laser operation of Tm:KGd(WO/sub 4/)/sub 2/ in the continuous-wave regime at room temperature

“…Note that the shorter radiative upper level lifetime calculated in [20] for a 3.5% Tm-doped KGdW (Table I) was derived from unpolarized spectral measurements by the Judd-Ofelt theory which was shown in [27] to be less accurate in the case of the Tm-ion. It is difficult to compare the results of [19] and those depicted in Fig. 1.…”

“…It was only recently that the spectroscopic properties relevant to laser operation were studied for flux grown Tm:KGdW by a part of the present authors [18], [19], [25] and also by others [20], [26]. While in [20], [26] only unpolarized spectra were presented, the systematic studies in [19] and [25] were performed in the orthogonal frame of the optical indicatrix. In the C2/c space group the lattice parameters of the monoclinic KGdW are nm, nm, nm and with .…”

“…The measured decay time of the upper laser level ( F population was estimated to decrease from 1710 to only 1530 s for Tm doping varying from 1 to 10% [19]. The radiative lifetime of 1.31 ms was calculated for Table I from the updated emission cross sections (cross section comparison method) which is equivalent to the requirement that the Fuechtbauer-Ladenburg and the reciprocity methods provide close results for the cross sections (the partition functions and zero-line energy used in the calculation can be found in [19]). This approach follows closely the strategy adopted in the review [2] for comparison of various Tm-hosts.…”

“…to similar estimations in Tm:KYW because of the different methods and crystal orientations used. Thus, for instance, in [19] and in the present work the reciprocity method was used to calculate the emission cross section from the measured absorption. In contrast, in [15] the emission cross section (for unspecified polarization in the -plane of 15%-doped Tm:KYW, see Table I) was estimated following the Fuechtbauer-Ladenburg method of calculating it from measured spectral density of the fluorescence and assuming .…”

1.84 μ m emission of Tm3+ sensitized by Yb3+ ions in monoclinic KGd(WO4)2 single crystals

“…6,7 Recently, we demonstrated the successful crystal growth of Tm 3+ : KGW and studied its spectroscopic properties. 8 We obtained highly efficient tunable laser operation in the cw regime at room temperature on the 3 F 4 → 3 H 6 transition. 9 In this paper, we have characterized the near infrared emission at 1.84 m of thulium ions in KGW single crystals codoped with Yb 3+ and Tm 3+ ions by pumping at 940 nm.…”