通过测量掺杂KNSBN晶体光折变光栅记录和擦除动态特性，首次分析了掺杂KNSBN晶体中的电子一空穴竞争。根据耦合波理论，指出，响应时间越快的晶体，电子一空穴竞争越激烈，因而导致净调制折射率越小，衍射效率越低。最后，分析了空穴产生的原因，并估算有效载流子浓度为1015/cm3量级。

The electron-hole competition in doped KNSBN crystal is analyzed for the first time by measuring the recording and erasing kinetics of doped KNSBN crystals. It is shown that the shorter the response time, the sharper is the competition between electrons and holes in doped KNSBN crystals. So it leads to the net index modulation and the diffraction efficiency smaller. The reason of the hole carriers increasing has been analysed in reduced Co: KNSBN crystals. The effective carrier densities are estimated as the order of 10 15 cm-3.