基于光擦除和双光束耦合的基本原理，提出了一种多级光探测的方法。用带导模型和耦合波方程建立了理论公式。用三块Ce:KNSBN晶体和He-Ne激光进行了实验演示。理论分析与实验研究均表明所提出的方法是可行的。

The method of multi-stage optical detection is presented based on the principle of optically erasing and two-beam coupling. The theoretical formula about the device is built by using the coupling wave equation and band-transport model. An experimental demonstration is done by using Ce∶KNSBN crystals and He-Ne laser. The feasibility of the method is proved by theoretical analysis and experimental demonstration.