波前分割DOE阵列半导体激光器光束的品字形整形

半导体激光器（LD）输出光束受工作电流、个体差异的影响，发散角、输出光强出现波动。常规衍射光学元件（DOE）的激光光束整形设计只针对特定的输入输出光场，使用宽容度比较小。文中在LD 的整形中利用DOE 阵列化的处理，输入光场被分割成许多小单元，不同强度的光重新在成像平面内预定的区域内叠加，实现对光束的整形。用均匀平面波设计阵列DOE 每个单元，把高斯分布的球面波整形成品字形光强分布，衍射效率为90.53%，均匀性大约为96%；发散角在快、慢轴方向上2~16的范围内变化，均匀性为95.8%以上、衍射效率为90%以上；在离焦量16 m 内，光束质量变化不大。阵列DOE 提高了LD 光束整形系统的稳定性。

Shaping laser diode beam into three rectangles by a DOE array to divide input wavefront

The intensity distribution and the divergence of the laser diode (LD) output beam are variable with the different operating current and individual differences. The design of conventional diffractive optical element(DOE) to shape LD beam depends on the intensity distribution of the LD input and output beam, so the tolerance for the input LD beam is very small. A DOE array was put forward to shape the LD beam into three rectangles. It consisted of many DOE units, and each DOE unit could shape the corresponding small segment wavefront into needed output shapes, and all light diffracted by all DOE units was super-positioned on the output plane. Using the above DOE array laser shaped method, three rectangles intensity distribution were realized from Gaussian beam with the diffraction efficiency of 90.5% and the uniformity of 96%. When the half divergence angle of the LD varied from 2to 16in slow and fast axis direction respectively, the diffraction efficiency maintain was approximate 90% and its uniformity was more than 95%. When the defocus of the lens to collimate LD beam varied from -16 m to 16 m,numerical experiments indicate that uniformity and the diffraction efficiency of the shaped beam by the DOE array do not vary. The stability of the LD beam shaping system is improved.