近化学配比LiNbO_3晶体双色光全息记录的实验研究

Experimental Investigation of the Two-Color Holographic Recording in Near-Stoichiometric LiNbO_3 Crystals

实验用红光记录紫光敏化,研究了几种不同掺杂浓度和氧化还原状态的近化学配比铌酸锂晶体的双色全息记录特性,如其饱和衍射效率和记录灵敏度的变化规律。实验结果表明,晶体的饱和衍射效率随透射光强与紫外光强比值的增加先增加后减小,而记录灵敏度在不断减小。Mn含量相同时,Tb含量越高的晶体饱和衍射效率越高,而记录灵敏度越低。Tb含量相同时,含Mn比不含Mn的晶体的饱和衍射效率低,但记录灵敏度更高。还原晶体的饱和衍射效率和记录灵敏度均比氧化晶体高。记录光与敏化光的比值、掺杂浓度和氧化还原状态对晶体的全息特性产生影响。通过适当调整上述参数之间的关系,可对材料的全息记录特性进行优化。

We investigate systematically two-color holographic recording properties such as the saturated diffraction efficiency and recording sensitivity in the near-stoichiometric LiNbO3 crystals with different dopants and oxidation-reduction（O-R） states.In the two-color recording experiment,the volume holographic gratings is recorded by red light,simultaneously sensitized by violet light.The results show that the saturated diffraction efficiency increases and later decreases with the increase of the ratio of recording light intensity to sensitizing beam intensity,but the sensitivity decreases gradually.Higher Tb-doping density makes higher diffraction efficiency but lower sensitivity when the Mn-doping density keeps the same.Crystal doping with Mn makes higher sensitivity but lower diffraction efficiency when the Tb-doping density keeps the same.The saturated diffraction efficiency and recording sensitivity of the reduction crystal are higher than those of the oxidation crystal.The saturated diffraction efficiency and sensitivity depend on the ratio of recording light intensity to sensitizing beam intensity,the doping concentration and the O-R state.An optimization may be obtained by further modifying these conditions appropriately.