Growth, spectroscopy, and laser performance of a 279  μm Cr,Er,Pr:GYSGG radiation-resistant crystal

Abstract

We demonstrate the growth, spectroscopy, and laser performance of a 2.79 μm Cr,Er,Pr:GYSGG radiation-resistant crystal. The lifetimes for the upper laser level (4)I(11/2) and lower laser level (4)I(13/2) are 0.59 and 0.84 ms, respectively, which are due to the doping of the Pr(3+) ions. A maximum pulse energy of 278 mJ operated at 10 Hz and 2.79 μm is obtained when pumped with a flash lamp, which corresponds to the electrical-to-optical efficiency of 0.6% and a slope efficiency of 0.7%. A maximum average power of 2.9 W at 60 Hz is achieved, which corresponds to the electrical-to-optical efficiency of 0.4% and slope efficiency of 0.8%. Compared with a Cr,Er:YSGG crystal, the Cr,Er,Pr:GYSGG crystal can be operated at a higher pulse repetition rate. These results suggest that doping deactivator Pr(3+) ions can effectively decrease the lower laser level lifetime and improve the laser repetition rate. Therefore, the application fields and range of the Cr,Er,Pr:GYSGG laser can be extended greatly due to its properties of radiation resistance and high repetition frequency.

Growth, structure, and spectroscopic properties of a Cr3+, Tm3+, Ho3+, and Pr3+co-doped LuYAG single crystal for 2.9 μm laser

“…The Cr 3+ and Tm 3+ ions have been chosen as the sensitizer in many Ho 3+ -doped laser crystals and ceramics [16][17][18][19], which can efficiently absorb and transfer the pumping energy to the Ho 3+ activator ions. And the Pr 3+ ions used as the deactivator have acquired good results in decreasing lifetimes of the lower laser energy levels in several crystals, such as Er,Pr:GYSGG [7], Cr,Er,Pr:GYSGG [20], Er,Pr:GGG [21], Ho,Pr:LiLuF 4 [22], and Yb,Ho,Pr:YAP [23] crystals, et al These results provide useful references to utilize the sensitizer of co-doping Cr 3+ and Tm 3+ ions and the deactivator of the Pr 3+ ions for the Ho 3+ ions.…”

Highly efficient dual-wavelength mid-infrared CW Laser in diode end-pumped Er:SrF2 single crystals

“…Er 3+ ion based laser materials operating at around 2.8 μm have attracted increasing interest in recent years because of their various important applications1234. Lasers around this specific region can be utilized for medical surgery, dentistry, remote sensing etc, because of the strong water absorption around this spectral region56.…”

“…However, the drawback of high Er 3+ doping is that the crystal quality and thermal conductivity will degenerate significantly with the increasing of Er 3+ concentration. Co-doping deactivating ions, such as Pr 3+  1679, Nd 3+  210, Ho 3+  11 etc, is another way to overcome this “bottleneck” effect by effectively depopulating the Er 3+ : 4 I 13/2 level, but only a few have achieved laser output. Furthermore, after co-doping deactivating ions the theoretical slope efficiency limit will be lower, because part of the energy of Er 3+ ions is depleted by deactivating ions1213.…”

“…Furthermore, after co-doping deactivating ions the theoretical slope efficiency limit will be lower, because part of the energy of Er 3+ ions is depleted by deactivating ions1213. And deactivating ions also will have inevitable negative effect on Er 3+ : 4 I 11/2 level due to complicated energy transfer process19. Hence, host materials that can achieve mid-infrared CW laser under low Er 3+ doping concentration would be more favorable.…”

“…In Er 3+ based oxide crystals, such as Y 3 Al 5 O 12 (YAG)111415, Gd 3 Ga 5 O 12 (GGG)16 and Gd 3−x Y x Sc 2 Ga 3 O 12 (GYSGG)17 etc, the Er 3+ doping concentrations vary from 30 at.% to as high as 50 at.%. Lu 2 O 3 crystal has the lowest Er 3+ doping concentration of 7at.% among that group8.…”