Comparison of a diode pumped Er:YSGG and Er:YAG laser in the bounce geometry at the 3 μm transition

Abstract

A comparative study is made of the laser crystals 50 at. % Er:YAG and 50 at. % Er:YSGG. Both lasers are constructed in the bounce geometry with quasi continuous wave (QCW) diode pumping. In Er:YAG, pulse energies of up to ~31mJ, slope efficiency of 12.6% and a red-shift in laser wavelength are observed with a final and dominant wavelength of 2.936μm. In Er:YSGG, higher performance is achieved with pulse energies of ~55mJ, slope efficiency of 20.5% and a single transition wavelength of 2.797μm observed. The study indicates that diode pumped Er:YSGG is a superior laser source at 3μm than Er:YAG and it has greater energy storage potential for Q-switched operation.

Efficient tri-wavelength actively Q-switched Yb:GAGG laser

“…The study on its spectroscopic properties showing that the emission cross section amount to 1.05 Â 10 À20 cm 2 at the emission peak of 1024 nm. The fluorescence lifetime of 1.38 ms is longer than some other gallium garnets [2,7,[11][12][13] and it indicates the Yb:GAGG crystal has a great potential to get high energy pulse through Q-switching action [14]. As the reported, passively Q-switched operation has been demonstrated with many Yb-doped crystals [15,16], however, the active Q-switched laser action with acousto-optic (AO) modulator has not attracted much more attention.…”

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

“…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.…”

Optical chopper Q-switching for flashlamp-pumped Er,Cr:YSGG lasers

“…Self-termination of free-running, flashlamp-pumped Er,Cr:YSGG Whilst Yttrium Aluminium Garnet (YAG) is commonly used as a host for   3 m erbium lasers, Yttrium Scandium Gallium Garnet (YSGG) is a potentially superior candidate for Q-switching [12] because of its longer upper laser level lifetime (1.3 ms in YSGG compared to 0.12 ms in YAG [13]) This longer upper laser-level lifetime also makes the YSGG based lasers more suited to "slow" methods of Q-switching. With the YSGG host, the primary laser wavelength is  = 2.794 m, and when flashlamp-pumped, the erbium ions are co-doped with chromium to increase pump energy absorption, giving Er,Cr:YSGG [14].…”

“…CW operation occurs via inter-ionic up-conversion processes which together act as an aid to population inversion [12].…”