采用后重氮偶合法，合成了一种新型含咔唑类聚磷腈有机光折变材料。采用氢谱核磁共振法，红外光谱法，紫外-可见吸收光谱法，热重法和差示扫描量热法对该聚合物进行表征和分析，结果表明，该聚合物具有良好的热稳定性，在230 ℃开始分解，450 ℃时基本分解完全。UV-Vis表明波长在360 nm与570 nm之间的宽的吸收带是由于共轭长度的增加产生的，因此可以调整参加偶合反应的重氮盐比例，来控制偶氮生色团功能组分的接入含量。在未使用外加电场及事先极化的条件下对聚合物进行了二波耦合与四波混频实验，证明了聚合物的光折变特性。得到聚合物P-2和P-3的二波耦合增益系数分别为38 cm-1和53.6 cm-1，聚合物P-2和P-3的四波混频衍射效率分别为2.7%和8.1%。

We investigate the nonvolatile holographic storage characteristics of near-stoichiometric LiNbO3:Fe:Mn crystals with different Li2O contents. Experimental results indicate that the optimal value of Li2O content is about 49.6 mol%. Nonvolatile sensitivity S′ considerably improved to 0.15 cm/J because of the use of near-stoichiometric LiNbO3:Fe:Mn with 49.6 mol% Li2O.

The effect of the diminution of the sensitizing intensity from initially high value on two-center recording is experimentally and theoretically investigated. A linear diminution of the sensitizing intensity is designed, and three different diminution rates are employed for the experimental investigation. The results show that the dynamic range can be improved by reducing the diminution rate of the sensitizing intensity. Compared with that of traditional two-center recording, the recording sensitivity obtained in the experiment is more improved when the maximum dynamic range is achieved. The effect of the diminution of the sensitizing intensity on grating uniformity and the effect of the initial sensitizing intensity on the recording sensitivity are theoretically investigated.

为了得到有偏压的中心对称双光子光折变晶体中存在多变量空间灰孤子的结果,基于中心对称双光子光折变晶体中空间灰孤子的基本理论，采用数值方法推导出了中心对称双光子多变量空间灰孤子归一化包络解的积分形式,并对其特性进行研究。结果表明: 这种多变量空间灰孤子是由多束偏振方向和波长都相同的互不相干光束耦合形成的。当多变量空间灰孤子只包含有1个或2个光束分量成分时，它自动退化到中心对称双光子空间灰孤子或中心对称双光子非相干耦合灰-灰空间孤子对的情况。当这一多变量空间灰孤子在有偏压的中心对称双光子光折变晶体中传播时，各分量成分光束都能稳定传播。

为了得到一束高斯光束和两束高斯光束的相互作用在有外电场的双光子光伏光折变材料中的演化结果, 将高斯光束作为入射波,采用数值方法求解波传播方程。研究结果表明: 在外加电场、光强峰值分别与晶体参量匹配的情况下, 一束高斯光束能演化为稳定的屏蔽光伏明孤子, 而在不匹配时,一束高斯光束在传播过程中则呈现周期性压缩或膨胀现象。同时也发现: 在作用距离范围内, 同相位的两高斯光束相互吸引, 并伴随有融合现象；而相位相反的两高斯光束相互排斥, 且其排斥作用随着光束初始间距的减小而增加, 当两高斯光束的相位差位于区间(0, π)和(-π,0)时, 其相互作用过程中伴有能量的转移, 两区间中能量转移方向相反。

2 Nonvolatile two-color holographic recording gated by incoherent ultraviolet (UV) light centered at 365 nm is investigated in near-stoichiometric lithium niobate crystals. The influence of thermal treatment on the two-color recording is studied. The results show that thermal reduction tends to improve the two-color recording performance, whereas thermal oxidation degrades the two-color recording. With an incoherent 0.2-W/cm2 UV gating light and a 0.25-W/cm2 semiconductor recording laser at 780 nm, a two-color recording sensitivity of 4\times10^{-3} cm/J and a recording dynamic range characterized by M/# of 0.12 are achieved in a 2.2-mm thermally reduced near-stoichiometric lithium niobate crystal. We attribute the improvement to the prolonged lifetime of small polarons and the increased absorption at the gating wavelength due to thermal reduction.

为了研究在有外电场的中心对称光折变材料中一束高斯光束及两束高斯光束相互作用的演化,将高斯光束作为入射波,采用数值方法求解波传播方程。结果表明,当外加电场,光强峰值和束腰参量分别与晶体匹配的情况下,一束高斯光束能演化为稳定的屏蔽空间明孤子,而在不匹配时,一束高斯光束在传播过程中则呈现周期性的压缩或膨胀现象。同时也发现,在作用距离范围内,两束同相位高斯光束相互吸引,并伴随着融合现象,两束反相位高斯光束相互排斥,且排斥作用随着光束初始间距的减小而增加。

Nonvolatile holographic recording is performed with green light in LiNbO3:Ce:Cu crystals. The refractive-index change and the recording sensitivity are times better than those obtained by recording with red light, and higher optical fixing efficiency is obtained. Correspondingly, theoretical investigations are given.