Son Taehwang, Moon Gwiyeong, Lee Changhun, Xi Peng, Kim Donghyun
School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Korea.
Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing, 100871, China.
Nanophotonics. 2022 Oct 24;11(21):4805-4819. doi: 10.1515/nanoph-2022-0546. eCollection 2022 Dec.
Near-field optics is essential in many nanotechnology applications, such as implementing sensitive biosensing and imaging systems with extreme precision. Understanding optical near-fields at the nanoscale has so attracted the considerable research interest, which use a variety of analytical approaches, most notably near-field scanning microscopy. Here, we show defocused point localization mapped accumulation (DePLOMA), which can overcome many weaknesses of conventional analytical methods. DePLOMA is based on imaging fluorescence emitters at an out-of-focal plane. The acquisition, collection, and accumulation of the position and fluorescence intensity of emitters moving above nanostructures can generate three-dimensional near-field maps of light distribution. The idea enables super-resolution liquid-phase measurements, as demonstrated by reconstruction of near-field created by nanoslits with a resolution determined by emitter size. We employed fluorescent emitters with a radius of 50 and 100 nm for confirmation. The axial resolution was found to be enhanced by more than 6 times above that of diffraction-limited confocal laser scanning microscopy when DePLOMA was used.
近场光学在许多纳米技术应用中至关重要，例如实现具有极高精度的灵敏生物传感和成像系统。了解纳米尺度下的光学近场已吸引了大量研究兴趣，人们使用了各种分析方法，其中最著名的是近场扫描显微镜。在此，我们展示了散焦点定位映射累积法（DePLOMA），它可以克服传统分析方法的许多弱点。DePLOMA基于在焦平面外对荧光发射体进行成像。对在纳米结构上方移动的发射体的位置和荧光强度进行采集、收集和累积，可以生成光分布的三维近场图。这一想法实现了超分辨率液相测量，如通过重建由纳米狭缝产生的近场所示，其分辨率由发射体大小决定。我们使用半径为50和100纳米的荧光发射体进行了验证。当使用DePLOMA时，轴向分辨率比衍射极限共聚焦激光扫描显微镜提高了6倍以上。
