The spectroscopy and lasing of monoclinic Tm:KY(WO₄)₂crystals

Abstract

The principal spectroscopic and lasing characteristics of a Tm(15%) : KY(WO 4 ) 2 crystal were investigated. The transition cross sections, the luminescence quantum yield, and the lifetime and the nonlinear depopulation coefficient of the upper active state were also determined. The slope efficiency of lasing at the 1950 nm wavelength was 45%. The feasibility of tuning in the spectral range 18501 950 nm was demonstrated in principle. S N Bagaev, S M Vatnik, A P Maiorov, D V Plakushchev Institute of Laser Physics, Siberian Division of the Russian Academy of Sciences, prospekt akad. Lavrent'eva 13/3,

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

“…The first demonstration of Tm lasing on the F H transition in monoclinic double tungstates was realized in 1997 with Xe-flash lamp pumping where Tm:KY(WO ) (Tm:KYW) and Tm:KGd(WO ) (Tm:KGdW) rods sensitized with Er and Yb operated at cryogenic temperatures and wavelengths of 1920 and 1930 nm, respectively [14]. Soon afterwards continuous-wave (CW) room-temperature operation of highly doped (15%) Tm:KYW was demonstrated with longitudinal Ti:sapphire laser pumping near 800 nm [15]. Codoping of Tm:KYW with Yb for InGaAs diode pumping at 980 nm with subsequent excitation transfer was studied in [16] but laser experiments revealed no practical advantages as compared to direct 800 nm pumping by AlGaAs diodes [21].…”

“…We note that the combination of broad fluorescence line, large emission cross section and relatively low upper level lifetime (Table I) is an unique advantage for future experiments on passive mode-locking with such lasers and the generation of femtosecond pulses by an all-solid state laser system tunable in the 2-m spectral range. Tm-doped double tungstates have an absorption line centered at 800-802 nm [15], [25] with a broader longwave wing very suitable for diode pumping. The first demonstration of Tm lasing on the F H transition in monoclinic double tungstates was realized in 1997 with Xe-flash lamp pumping where Tm:KY(WO ) (Tm:KYW) and Tm:KGd(WO ) (Tm:KGdW) rods sensitized with Er and Yb operated at cryogenic temperatures and wavelengths of 1920 and 1930 nm, respectively [14].…”

“…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 . It was shown in [16] that the Fuechtbauer-Ladenburg method results in larger ( cm maximum emission cross section for Tm:KYW than the reciprocity method ( cm which was used also by us.…”

Growth and spectral properties of Yb,Tm:YAG crystal

“…1.6-2.0 m lasers are safe to human eyes and thus are also widely used in medicine. Most solid-state 1.6-2.0 m laser operations are based on transition 3 F 4 → 3 H 6 in thulium ions and the performance of the thulium ions in a number of solid-state host has been widely studied and laser operation has been successfully realized [1][2][3][4][5][6][7][8][9][10][11][12][13].…”

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

“…% Tm 3+ :KY͑WO 4 ͒ 2 was demonstrated with longitudinal Ti:sapphire laser pumping near 800 nm. 5 They found that the thulium concentration must be high enough to ensure efficient pumping, but low enough to minimize concentration quenching effects due to cross-relaxation-type ͑ 3 H 4 + 3 H 6 → 3 F 4 + 3 F 4 ͒ and nonradiative energy transfer between active ions. In 2002, Yb 3+ , Tm 3+ :KY͑WO 4 ͒ 2 was studied for InGaAs diode pumping at 980 nm with subsequent excitation transfer from Yb 3+ to Tm 3+ ions at several dopant concentrations.…”