提出一种增加轴锥镜对的同轴反射式光学结构激光发射天线方案,通过对入射光束的光强重新排布,降低同轴反射式结构固有的中心遮拦造成的能量损失,提高光能利用率.运用衍射光学原理分析并模拟了单色高斯光束经过轴锥镜对后传播至天线光阑平面处的光场分布,比较了普通同轴反射式天线和高光能利用率天线在不同入射光束腰半径、不同线遮拦比下的发射光能利用率.结果表明:高光能利用率天线在线遮拦比0.1和0.25的情况下,通过合理调整入射光束腰大小,光能利用率分别可达到99%和96%以上,远高于传统的同轴反射式天线.分析了高光能利用率天线发射光束的远场光强分布,发现其进入接收天线口径内的光场可近似为平顶分布.
A scheme of coaxial reflective laser communication antenna added an axicon pair was proposed. This antenna could rearrange the light intensity distribution of the incident beam, leading to a great reduction of the energy loss caused by the central obscuration of the coaxial reflective structure and an increasing of the light-energy-utilization-ratio. Using the diffraction optical principle, the optical field distribution of the monochromatic Gaussian beam propagating to the antenna optical stop plane passed the axicon pair was analyzed and simulated, and the transmitting light energy utilization ratios of the ordinary coaxial reflective antenna and the high light-energy-utilization-ratio antenna in different incident beam waist and line obscuration ratios were compared. It was found that at the line obscuration ratio of 0.1 and 0.25, the light-energy-utilization-ratios of the high light-energy-utilization-ratio antenna were more than 99% and 96% through adjusting the incident beam waist diameter reasonably, which were much highest than that of the traditional coaxial reflective antenna. The far-field optical intensity of the light-energy-utilization-ratio antenna transmitting beam was analyzed, and the the light intensity in the receiving antenna aperture can be considered as a flat top distribution.