亚百纳米超分辨光学成像新方法

The resolution of conventional optical equipment has long been restricted by the diffraction limit, which was previously considered as an impassable chasm. Recently, this problem is partially solved by some conspicuous ideas,for example, the technique based on nonlinearity of fluorescence or on high spatial frequency of plasmonic wave etc., but their utilization scales are confined by the evident weaknesses like scanning speed and applicable materials. In this program, a absolutely new method that is based on microfiber evanescent wave illumination is proposed. By collecting the scattered evanescent wave near the surface of sample, this method possesses super-resolution capacity and a wide utilization scale. A viewing field no less than 2μm×2μm and a resolution of 80nm can be expected if a microscope integrated with this approach is the gole of this program.

阿贝衍射定律一直被认为是光学系统最终分辨能力的极限。近年来，一些基于荧光非线性或表面等离子波效应的超分辨显微成像方法不断出现，引起了广泛关注，但存在成像频率、样品材料要求高等的缺陷而极大限制了其应用。本项目提出了一种基于微光纤的全新显微成像技术。它采用微光纤形成的表面高频倏逝场来照明样品，通过收集样品表面倏逝波散射信号来实现宽场超分辨显微成像的目的。彻底改变了传统近场光学显微镜利用微光纤纳米端头近场照明、近场探测，扫描成像的模式，实现了近场照明、远场宽场的超分成像，因此该技术具有使用方便，无需荧光标记、对样品选择性小等特点，具有更为广泛的应用前景。本项目希望能够实现在可见光区2μm×2μm视场内，达到80nm的横向分辨率。

近几十年来，随着生命科学和材料等领域的飞速发展，人们在尝试各种方法突破衍射极限，以实现超分辨显微成像。荧光标记相关的显微成像在超分辨中取得了很大的进展，然而，荧光标记面临着光漂白和光毒性的缺点使其在生物成像中具有很大的限制。本项目提出了基于非标记的宽场超分辨显微成像的几种方法：通过多角度照明进行相位成像获取样品的相位信息，实现了三维折射率横向200nm，纵向400nm的成像分辨率；采用物镜激发表面波产生大波矢照明样品，进行移频超分辨成像，实现120nm-120nm的分辨率，得到刻蚀深度90nm的样品表面形貌；采用纳米线作为局域光源，结合薄膜波导产生全方位的照明倏逝波，可以实现70nm线宽，1000um2视场的移频超分辨成像。