Creation of identical multiple focal spots with prescribed axial distribution.
Creation of identical multiple focal spots with prescribed axial distribution.
复制标题
创建具有指定轴向分布的相同多个焦点
DOI：
10.1038/srep14673
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发表时间：
2015-10-01
影响因子：
4.6
通讯作者：
Zhan Q
中科院分区：
文献类型：
--
作者：
Yu Y;Zhan Q
我们提出了一种构造同轴等距多个焦点的方案，每个焦点具有相同的强度分布，并且具有预定的数目和间距。为了实现这一点，天线的辐射场被反转，然后由大数值孔径物镜收集。分别利用电流、磁流和电磁电流分布的余弦平方锥形三种线源的辐射方向图，产生强度分布完美球对称的主要纵向偏振亮点、方位偏振甜甜圈和焦斑。通过求解天线辐射场的逆问题，可以很容易地推导出产生这些相同的多个焦点所需的4PI聚焦构型的光瞳平面上的照度。这些独特的焦场分布可能在激光直写和光学显微镜以及沿光轴的多粒子捕获、对准和加速方面有潜在的应用。
We present a scheme for the construction of coaxially equidistant multiple focal spots with identical intensity profiles for each individual focus and a predetermined number and spacing. To achieve this, the radiation field from an antenna is reversed and then gathered by high numerical aperture objective lenses. Radiation patterns from three types of line sources, i.e., the electric current, magnetic current and electromagnetic current distributions, with cosine-squared taper are respectively employed to generate predominately longitudinally polarized bright spots, azimuthally polarized doughnuts and focal spots with a perfect spherically symmetric intensity distribution. The required illuminations at the pupil plane of a 4Pi focusing configuration for the creation of these identical multiple focal spots can be easily derived by solving the inverse problem of the antenna radiation field. These unique focal field distributions may find potential applications in laser direct writing and optical microscopy, as well as multiple-particle trapping, alignment and acceleration along the optical axis.