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

Abstract

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 4F3/2–4I13/2 (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 λ ~ 1786 nm reaches 17.5%, which results in an ~6.6 mJ Raman pulse. For E || N g , the conversion efficiency increases up to 22.5% and generation of an ~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.