基于纯相位衍射光学元件模式选择双半高斯空心激光器的研究

We focus on gaining a laser light source of double half-Gaussian distribution hollow beams, which has a large hollow region in which the intensity is zero and remarkable intensity contrast in the inner beams and good propagation characteristic, by using the pure phase diffractive optical elements and choosing the laser pattern. For the first time we obtain the algorithm to resolve the laser mode self-consistent integrals of laser optical resonator containing pure phase diffractive optical elements, and give the correct methods to remove phase catastrophe point of diffractive optical elements by applying filter technology in the digital image processing and solve the phase distribution created by the diffractive optical elements in oblique incident beams. Besides, the software to get pure phase diffractive optical elements, which satisfies resonator self reproduction condition in vertical and oblique light field, will be designed. On the basis of the above methods, the experiment of double half-Gaussian distribution hollow beams laser will be studied. The study of high-energy electro-optically tuned laser employing hollow beams as well as self-phase-matching third-harmonic conversion is being carried out. Meanwhile, the research on diffracting propagation characteristic of double half-Gaussian hollow beams in the atmosphere is undergoing. This research on the new type hollow laser light source and relative technology will lay solid foundation for micro-particle optical maneuvering, atomic cooling, optical information processing, material science, stealth detection and control etc. Moreover, it can provide a new way to realize high energy pulse laser and ultraviolet laser with wide bandwidth as well.

本研究着眼于利用纯相位型衍射光学元件选择激光模式来获得具有较大空心区域光强为零、光束内侧极高光强对比度和良好传输特性的双半高斯强度分布的空心激光光源。首次给出求解含有纯相位型衍射光学元件激光光学谐振腔模式自再现积分方程的算法、利用数字图像处理中的滤波技术消除衍射光学元件相位突变点及求解基于光束斜入射条件下衍射光学元件相位分布的解决途径。编制以正入射和斜入射光场为初始条件并满足激光光学谐振腔模式自再现条件的纯相位型衍射光学元件的设计软件。在此基础上开展双半高斯空心激光器的实验研究，并利用空心光源进行高能电光调Q及自相位匹配三次谐波转换技术的研究。同时开展双半高斯强度分布空心激光束在大气中衍射传输特性的研究。这种新型空心激光光源及相关技术的研究将为微观粒子光学操控、原子冷却、光信息处理、材料科学以及隐身探测、隐形控制等领域的应用奠定坚实基础，也为实现高能脉冲激光器及宽带紫外激光器提供新的思路。

项目利用衍射光学元件选择激光模式实现了双半高斯空心激光输出。求解了含有纯相位型衍射光学元件激光光学谐振腔自再现积分方程的算法、利用数字图像处理中的滤波技术消除衍射光学元件相位突变点。编制了以斜入射光场为初始条件并满足激光光学谐振腔的自再现条件的纯相位型衍射光学元件的设计软件。在此基础上开展了双半高斯空心激光器实验研究，并利用了空心光源进行高能电光调Q及自相位匹配三次谐波转换技术的研究。同时开展了双半高斯空心激光束在大气中衍射传输特性的研究。研究成果可以应用于具有倾斜和折叠光路等特征的复杂光学系统中，同时还可以利用倾斜放置的DOE特性来校正需要多片透镜组和才能校正的像差，不仅起到简化系统、降低成本的作用，还极大的提高了光学系统的性能。本项目取得的成果可为微观粒子的光学操控、原子冷却、光信息处理、材料科学以及隐身探测、隐形控制等领域的研究及应用打下坚实的基础。通过本项目的研究，我们在Optics Express、Applied Optics、Optics Communications、 IEEE Photonics Technology Letters和Journal of Applied Physics等学术期刊上发表了SCI论文15篇，获得国家发明专利2项，培养2名博士生，12名硕士生。