Raman laser based on a KGd(WO4)2 crystal: generation of stokes components in the 1.7-1.8 μm range*

We have studied the lasing characteristics of a Raman laser based on an Nd:KGW crystal, converting multimode emission of a pulsed Nd:KGW laser with working transition F-4(3/2)-I-4(13/2) (1351 nm) to Stokes components with wavelengths in the 1700-1800 nm range. We show that when the pump polarization coincides with the N (m) axis of the optical indicatrix of KGW (E || N (m) ), the conversion efficiency for converting the pump radiation to the single second Stokes component with lambda similar to 1786 nm reaches 17.5%, which results in an similar to 6.6 mJ Raman pulse. For E || N (g) , the conversion efficiency increases up to 22.5% and generation of an similar to 15 ns pulse occurs on four Stokes components with wavelengths 1704, 1744, 1770, and 1786 nm due to involvement of 86 cm(-1), 767 cm(-1), and 901 cm(-1) vibrational modes in the stimulated Raman (SRS) process. We have determined the spectral distribution of the pulse energy. A total of 11 Stokes components are generated with participation of the indicated vibrational modes.