Experimental and theoretical study of phonon-assisted Raman generation in KGd(WO₄)₂ crystal

This paper investigated the characteristics of the phonon-assisted Raman generation in KGd(WO 4 ) 2 crystal pumped by short -band-width Q-switched pulses. The KGd(WO 4 ) 2 Raman laser pumped by 1064.15 nm pulse generates a phonon wave in the KGd(WO 4 ) 2 crystal besides the ordinary Stokes laser output at 1177.19 nm. A synchronous weak pumping laser beam at 1273.38 nm generates its Stokes laser at 1438.51 nm with the help of the generated phonon wave in the Raman crystal. For a given pumping pulse energy of 45.0 mJ at 1064.15 nm, corresponding to the pumping pulse energy at 1273.38 nm increasing from 0.89 mJ to 1.26 mJ, the obtained Stokes pulse energy at 1438.51 nm increases from 48.0 µJ to 59.8 µJ. For a given pumping pulse energy of 1.03 mJ at 1273.38 nm, corresponding to the pumping pulse energy at 1064.15 nm increasing from 40.4 mJ to 59.0 mJ, the obtained Stokes pulse energy at 1438.51 nm increases from 25.0 µJ to 122.4 µJ. The maximum pulse energy at 1438.51 nm is 125 µJ when the 1064.15 nm pump pulse energy is 55.0 mJ and the 1273.38 nm pump pulse energy is 1.26 mJ, respectively. An expression for the phonon-assisted Raman pulse intensity is derived. The simulation results are consistent with the experimental results on the whole.