为了测量激光与等离子体相互作用产生的散射光份额，获得黑腔耦合效率实验中的激光注入率，研制了基于神光Ⅲ原型装置的全孔径背向散射测量系统。该系统利用聚焦透镜收集散射光，通过离轴抛物面镜进行缩束，并采用二向色镜将散射光分为两个支路后分别进行受激布里渊散射和受激拉曼散射光的能量、时间过程和光谱测量。实验测量了有、无束匀滑条件下的散射光份额。结果表明，在当前实验条件下，通过束匀滑可有效降低散射光份额，提高激光注入率。

In order to measure the fraction of laser-entrance energy, which is carried out mainly through the measurement of the fraction of backscattering light, a full aperture backscattering station measurement system is developed on the Shenguang-Ⅲ prototype laser facility. The system collects backscattering light from the laser-plasma interactions by the focusing final lens and decreases the beam caliber by the off-axial parabolic mirror. Stimulated Brillouin and Raman backscattering light are separated by single-edge dichroic beam splitter. The backscattering light′s energy, history and spectra can be detected by the system. The energy fraction of backscattering light is measured with and without beam smoothing. The results indicate that the fraction of laser-entrance energy will increase and the energy fraction of backscattering light will decrease with beam smoothing.