A line-imaging optically recording velocity interferometer system (L-ORVIS) fitting the high-strain rate motion of solids as in shock wave experiments requires a high power single-mode laser. We have put forward a new illumination method which can increase threefold the luminosity of such a diagnostic. A modified illumination system is applied to the L-ORVIS which was implemented at ‘Shenguang-II’ laser facility. The modified L-ORVIS is applied to laser-driven shock wave experiments and platinum Hugoniots were obtained at both high pressure and low pressure.