中文摘要：

研究了不同畴腐蚀深度的掺镁铌酸锂二维六角可调阵列光分束器的分数Talbot效应.对不同Talbot分数β和不同畴腐蚀深度的阵列光分束器Talbot衍射像进行了数值模拟理论研究.模拟结果表明,Talbot分数β可以改变Talbot衍射像的周期及结构分布,而畴腐蚀深度可有效调制衍射像的光强分布.在理论研究的基础上,设计并制备了具有不同畴腐蚀深度的掺镁铌酸锂二维六角阵列光分束器,对其在不同Talbot分数β条件下的分数Talbot效应进行了通光实验研究,实现了畴腐蚀阵列光分束器对近场Talbot衍射光强分布的调制,实验结果与理论研究结果一致.

英文摘要：

The Talbot effect is a self-imaging phenomenon of near-field diffraction. When a plane wave is incident on a periodic diffraction grating, the image of the grating is repeated at regular distances away from the grating plane. A Talbot array illuminator is a device that splits singular light beam into an array of beams with periodical optical intensity based on Talbot effect. LiNbO_3（LN） crystal is a kind of practicable material for a Talbot array illuminator due to its perfect optical characteristics. Mg O-doped LiNbO_3（Mg LN） crystal shows shorter absorption edge wavelength and higher resistance to photorefractive damage than LN. Up to now, the usefulness and simplicity of Talbot effect have still aroused the interest of many scholars.In the conventional method, a Talbot array illuminator is fabricated by using high external electric field to modulate the phase difference. However, essentially, high external electric field restricts the Talbot array illuminator to applications in optical integration and optical micro structure devices. Now we are looking forward to a new way which avoids using high external electric field.In this paper, we systematically study the two-dimensional（2D） hexagonal tunable array beam splitter, which is fabricated by domain-etching in Mg LN crystal, and its fractional Talbot effect. The self-imaging phenomenon caused by Talbot effect in the Fresnel field for this phase array coherently illuminated is theoretically analyzed according to Fresnel diffraction theory. We numerically simulate the light intensity distributions of Talbot diffraction image under different values of Talbot coefficient β and different values of domain-etching depth. The simulation results show that β can change the array period and the structure distribution of the fractional Talbot diffraction image, and the domain-etching depth can modulate the light intensity distribution of diffraction image. Based on the numerical simulation results, the2 D hexagonal array beam splitters are fabricated with di