Microscopic lenses are paramount in solar energy harvesting, optical devices, and imaging technologies. This work reports an extraordinary focusing effect exhibited by a surface nanolens (i.e., with at least one dimension of subwavelength) that is situated in an evanescent field from the total internal reflection (TIR) of light illuminated to the supporting substrate above the critical angle. Our measurements show that the position, shape, and size of the surface area with enhanced light intensity are determined by the geometry of the nanolens and the incident angle, in good agreement with simulation results. This strong focusing effect of the surface nanolens is shown to significantly promote the plasmonic effect of deposited gold nanoparticles on the lens surface inlight conversion and to vaporize surrounding water to microbubbles by using low laser power. This work further demonstrates that the light redistribution by the surface nanolens in TIR enables a range of novel applications in selectively local visualization of specimens in fluorescence imaging, optical trapping of colloids from an external flow, and selective materials deposition from photoreactions.

中文翻译：

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全内反射模式下表面纳米透镜的非凡聚焦效果

显微透镜在太阳能收集，光学设备和成像技术中至关重要。这项工作报告了一个表面纳米透镜（即具有至少一个亚波长维度）所表现出的非凡聚焦效果，该表面纳米透镜在临界角以上从照射到支撑基板的光的全内反射（TIR）处在一个渐逝场中。我们的测量表明，具有增强的光强度的表面积的位置，形状和大小由纳米透镜的几何形状和入射角决定，与仿真结果非常吻合。表面纳米透镜的这种强聚焦作用显示出可显着促进透镜表面光转换时沉积的金纳米颗粒的等离子体效应，并通过使用低激光功率将周围的水汽化成微泡。这项工作进一步证明了表面纳米透镜在TIR中的光重新分布在荧光成像中的标本选择性局部可视化，外流胶体的光学捕获以及光反应中的选择性材料沉积方面实现了一系列新颖的应用。