在超快二波耦合配置下的LiNbO3:Fe晶体中写入了体相位栅,通过一定的脉冲写入方法进行飞秒脉冲写入光栅的衍射自增强实验,在双光写入饱和后进行单写入光照射,产生了持续1 h的衍射自增强,同时又发现在光栅写入未饱和的时候改为单光写入也产生了衍射自增强现象,持续2 h。随后从光调制角度分析了该自增强现象的理论原因：脉冲衍射光和写入光共同作用,提高了二者耦合程度,写入了新光栅,从而加强原光栅,导致衍射效率提高,从而证明飞秒脉冲写入光栅的读出擦除可抑制,这对提高光全息记录的读出质量有正面意义。

Writing a grating by femtosecond coherent pulses, there was an erasure of grating during the reading process, so it is important for research a self-enhancement method to restrain the erasure. In the configuration of femtosecond two waves mixing, two pulses wrote a grating in a LiNbO3:Fe, there was a self-enhancement effect by using a special method that controlled the sequence of femtosecond pulse′s writing: after the two pulse′s writing, single pulse wrote the old grating which made the self-enhancement continue 1 h. At the same time the other self-enhancement effect had been found when the grating was unsaturated and the input two pulses changed to a single pulse, and this self-enhancement continued 2 h. Then the research on the relationship between the writing ultrafast pulse and the writing time had been done, finally the reason analysis had been done with the modulation of femtosecond pulse. This study showed that the diffracted pulse light interacting with writing pulse increased the level of mixing, then a new grating had been written, which boosted up the old one, so that diffraction efficiency increased. The experiment proved that the grating erasure written by femtosecond pulse can be restrained, which was good news for a reading effect of hologram writing.