Crystal growth, spectroscopic characterization, and eye-safe laser operation of erbium- and ytterbium-codoped KLu(WO_4)_2

Abstract

Erbium (Er)- and Ytterbium (Yb)-codoped monoclinic KLu(WO4)2 single crystals were grown by top seeded solution growth-slow cooling method for several different doping concentrations. Growth parameters have been optimized to obtain macrodefect-free single crystals. Er energy levels involved in the 4I13/2-->4I15/2 were determined by 6 K polarized optical absorption. The maximum emission cross section for this electronic transition has been evaluated, being 2.85x10(-20) cm2 for E||Nm at 1535 nm. Laser oscillation in the 1.5 microm range was obtained by pumping the Yb ion at 980 nm and sensitizing Er. The maximum output power achieved was 152 mW, with 1.2% slope efficiency.

A general trend of rare earth ions in the KRE(WO4)2 double tungstates (RE=Y, Yb, Gd, Lu)

“…[9,6,32] corresponding to the Er 3+ ion in KYbW, KYW and KLuW hosts, respectively. In this case, the number of the energy levels for Er 3+ in KYbW, KYW and KLuW included in the fits was 58, 64 and 15 respectively.…”

“…The calculated B k q parameters presented in Table 4, chosen as a point of reference, are used as initial parameters in order to fit the experimental Stark energy levels of Yb 3+ in KYbW [36], Yb 3+ in KYW and in KGdW [18] and Yb 3+ in KLuW [32,37]. The fitting procedure was described in our previous work (Yb 3+ doped YAB) [38].…”

“…e Experimental energy levels taken directly from Ref. [32]. host KGdW [31], a smooth variation of CFPs is obtained through the RE series.…”

Thermal, Spectral and Laser Properties of Er3+:Yb3+:GdMgB5O10: A New Crystal for 1.5 μm Lasers

“…The Er 3+ and Yb 3+ co-doped materials have gained much interest as laser media for emitting eye-safe laser around 1.5 μm, which can be used in many important applications, such as optical communication, environmental sensing, and medical treatments [1,2,3,4]. Many types of laser crystals co-doped with Er 3+ and Yb 3+ ions have been investigated and have realized 1.5 μm laser operations successfully, such as Y 3 Al 5 O 12 , Y 2 SiO 5 , KY(WO 4 ) 2 , YVO 4 , YCa 4 O(BO 3 ) 3 and Sr 3 Y 2 (BO 3 ) 4 [5,6,7,8,9,10,11].…”

In-band pumped room-temperature Er:KY(WO4)2 laser emitting around 1.6 μm

“…Continuous-wave (CW) room-temperature laser operation was demonstrated for several Er-, Yb-codoped crystals: garnets [1], vanadates [2], oxoborates [3][4][5][6] and tungstates [7,8]. Here the ytterbium absorption band at 0.9-1.0 µm was used for pumping and energy transfer to Er ions was utilized.…”