Measurement of Raman scattering gain coefficient in large-aperture DKDP crystals irradiated by 351 nm pulses

Transverse stimulated Raman scattering (TSRS) gain coefficient in a large aperture 65% deuterated potassium dihydrogen phosphate (DKDP) is measured at 351 nm. The measurement involves the use of an optical fiber sensor system to detect Raman scattering light in the DKDP crystal. A Raman scattering gain coefficient of 0.109 cm/GW is obtained and will be used to set upper limit of the DKDP crystals in our laser facility to avoid the TSRS induced energy loss and laser damage. The effect of bulk damage on growth behavior of TSRS is also examined and it is found that bulk damage has little impact on the TSRS growth. Thus the influence of bulk damage on the measurement of TSRS gain coefficient can be ignored.