摘要
为了研究入射光偏振态和入射光瞳有效数值孔径对共聚焦全内反射显微术（CTIRM）的分辨率，即焦点横向半峰全宽和纵向倏逝场透射深度的影响，根据Richard-Wolf矢量衍射理论，计算并讨论了线偏振、圆偏振、径向偏振和切向偏振入射光在界面处的光强分布情况；同时计算了在三种不同的有效数值孔径（1．33～1．45，1～1．45和1～1．12）时，焦点半峰全宽和倏逝场透射深度的数值结果。计算结果表明，当有效数值孔径为1．33～1．45，入射波长为532nm时，径向偏振光在横向上可达144nm的半峰全宽，优于线偏振的330nm和圆偏振的360nm，超过了衍射极限。薄且大的有效数值孔径能够获得更小的半峰全宽，其上下限的平方差越大，透射深度越小。三种数值孔径中，1—1．45时的透射深度最小，为140nm。相比较其他偏振光，径向偏振光更适合作为共聚焦全内反射显微术的入射激发光，并能够通过优化有效数值孔径，获得样品近表面处的高横向分辨率和低轴向荧光噪声。
In order to study the effects of polarization state and effective numerical aperture on the focal full- width at half-maximum （FWHM） and evanescent depth in confocal total internal reflection Microscopy （CTIRM）, according to the Richard- Wolf theory, the intensity distribution in the interface is calculated and discussed with linearly, circularly, radially and azimuthally polarized beams, respectively. Meanwhile, the numerical calculations of FWHM and depth are researched for three different effective numerical apertures （1.33-1.45, 1-1.45 and 1-1.12, respectively）. The results indicate that the FWHM of radially polarized beam is 144 nm, breaking through the limitation of diffraction, which is also better than 330 nm of linearly and 360 nm of circularly polarized ones, by using 532 nm incident wave and 1.33-1.45 aperture. The sharper focuscan be got with the larger and thinner aperture. Also the smaller depth of transmission can be got with the larger difference of squares of upper and lower limits, for which 140 nm is the shallowest depth with 1-1.45 aperture. Compared to other polarizations, radially polarized beam is the most suitable choice for CTIRM. And by optimizing the effective numerical aperture, high horizontal resolutions and low axial fluorescent noise near the sample surfacecan be obtained simultaneously.
出处
《激光与光电子学进展》
CSCD
北大核心
2014年第1期93-100,共8页
Laser & Optoelectronics Progress
基金
中国科学院苏州生物医学工程技术研究所"一三五"规划重大突破项目(Y052031205)
苏州市应用基础研究计划(SYG201128)
关键词
成像系统
显微
偏振
衍射理论
共聚焦
全内反射
imaging sustems
microscopy
polarization
diffraction theory
confocal microscopy
total internal reflection
