Efficient subwavelength focusing of light with a long focal depth
Efficient subwavelength focusing of light with a long focal depth
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具有长焦深的高效亚波长光聚焦。
DOI：
10.1039/c5nr04133c
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发表时间：
2015-01-01
期刊：
影响因子：
6.7
通讯作者：
Wu, Xingkun
中科院分区：
文献类型：
--
作者：
Huang, He;Li, Qing;Wu, Xingkun
我们展示了一种有效的方法，远场亚波长聚焦的一种新的两个组件的轴棱锥结构。由光纤轴棱锥产生的环形光束使用微锥反射器聚焦，产生具有高达40°的高会聚角的准贝塞尔光束。中心焦斑直径为0.41λ，焦深为9λ，工作距离为35 μm，功率效率大于40%。我们进一步证明，实验刀口测量映射光束焦点强度同意与数值模拟的结构。这种方法在克服单元件轴棱锥的光学聚焦极限方面显示出明显的前景，并且在光学系统中的高公差、高分辨率应用中具有巨大的潜力。
We demonstrate an efficient method for far-field subwavelength focusing by a novel two-component axicon structure. Annular beams generated by a fiber axicon are focused using a micro-cone reflector, creating a quasi-Bessel beam with a high convergence angle of up to 40°. A center focal spot diameter of 0.41λ was achieved at a power efficiency of over 40%, with a focal depth of 9λ and a working distance as long as 35 μm. We further demonstrate that experimental knife-edge measurements mapping the beam focal intensity agree with numerical simulations of the structure. This method shows demonstrable promise in overcoming the optical focusing limit of single-element axicons and great potential for use in high tolerance, high-resolution applications in optical systems.