Spectral and laser properties of Er:Yb:Sr_3Lu_2(BO_3)_4 crystal at 15–16 μm

Abstract

An Er:Yb:Sr 3 Lu 2 (BO 3 ) 4 crystal was grown by the Czochralski method. Spectral properties of the crystal were investigated, including the absorption and fluorescence spectra and the fluorescence decay. The fluorescence quantum efficiency of the 4 I 13/2 level of Er 3+ ions and efficiency of energy transfer from Yb 3+ to Er 3+ ions were calculated. Endpumped by a diode laser at 970 nm in a hemispherical cavity, laser performance of a 1.08-mm-thick Z-cut Er:Yb:Sr 3 Lu 2 (BO 3 ) 4 crystal was investigated. Compared with those of Er:Yb:Sr 3 Y 2 (BO 3 ) 4 crystal obtained in the same experimental condition, lower threshold, higher maximum output power, and comparable slope efficiency were achieved in the Er:Yb:Sr 3 Lu 2 (BO 3 ) 4 crystal.

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

“…The output laser spectrum with four lines around about 1569 nm was observed. At present, although the laser performance of the Er:Yb:GMB crystal is still inferior to those of Er:Yb:YCa 4 O(BO 3 ) 3 (the output power of 250 mW at 1.54 μm and slope efficiency of 21.9%) [5,11] and Er:Yb:Sr 3 Y 2 (BO 3 ) 4 (1.3 W quasi-continuous-wave output power around 1.56 μm and slope efficiency of 20%) [9,15], the slope efficiency obtained in the Er:Yb:GMB (17.8%) is larger than that of Er:Yb:GMB (10.2%) [14]. On the basis of the thermal property and initial laser experimental results, the laser slope efficiency will be further enhanced provided that the crystal optical quality is improved and laser experimental conditions are optimized.…”

“…In Er-Yb codoped crystals, a large amount (~1 × 10 21 atoms/cm 3 ) of Yb 3+ ions are needed because the Yb 3+ ions are considered as a sensitizer to increase the absorbed pump energy and then transfer energy to the Er ions [15]. As the ionic radius of La 3+ (1.216 Å) is much larger than those of Er 3+ (1.004 Å) and Yb 3+ (0.985 Å), it is not easy for such a large amount of Yb 3+ ions to substitute for La 3+ ions [16].…”