Near-field focusing of the dielectric microsphere with wavelength scale radius
Near-field focusing of the dielectric microsphere with wavelength scale radius
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波长尺度半径介电微球的近场聚焦
DOI：
10.1364/oe.21.002434
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发表时间：
2013-01-28
期刊：
影响因子：
3.8
通讯作者：
Zhuang, Songlin
中科院分区：
文献类型：
--
作者：
Guo, Hanming;Han, Yunxuan;Zhuang, Songlin
重点对具有波长尺度半径的微球数值孔径（NA）和球差的成因进行了物理分析。我们证明，当微球与周围介质的折射率对比度（RIC）在1.5 ~ 1.75之间时，微球自然具有可忽略的球差和高NA。其原因是由于微球的表面形状和RIC引起的正球差和由于微球的波长尺度尺寸引起的焦移引起的负球差引起的球差补偿。我们证明，只有在1.5的近似区域内
We focus on physically analyzing the origins of the numerical aperture (NA) and the spherical aberration of the microsphere with wavelength scale radius. We demonstrate that the microsphere naturally has negligible spherical aberration and high NA when the refractive index contrast (RIC) between the microsphere and its surrounding medium is about from 1.5 to 1.75. The reason is due to the spherical aberration compensation arising from the positive spherical aberration caused by the surface shape of the microsphere and the RIC and the negative spherical aberration caused by the focal shifts due to the wavelength scale dimension of the microsphere. We show that, only within the approximate region of 1.5