Diode end-pumped dual-wavelength Er,Pr:GSAG laser operating at 2696 and 2828 nm

We demonstrated the 962 nm laser diode end-pumped Er3+, Pr3+ co-doped GSAG laser operated in dual-wavelength of 2696 and 2828 nm. The absorption and fluorescence spectra of Er,Pr:GSAG crystal were investigated to determine the potential of laser generation in mid-infrared wavelength regions. The lifetimes of Er3+ in GSAG crystal for the upper laser level I-4(11/2) and lower level I-4(13/2) are 0.18 and 0.47 ms, respectively, for co-doped Pr3+ ion. The maximum average output power of 344 mW is achieved. In addition, a series of investigations for Er,Pr:GSAG laser performance were launched on the pump pulse width, repetition frequency and resonant cavity length. The results indicate that the small pump pulse width and low repetition frequency are beneficial to decrease the thermal lensing effect and improve the laser efficiency and beam quality.