We developed adjustable and movable droplet microlenses consisting of a liquid with a high refractive index. The microlenses were prepared via ultrasonic shaking in deionized water, and the diameter of the microlenses ranged from 1 to 50 μm. By stretching the microlenses, the focal length can be adjusted from 13 to 25 μm. With the assistance of an optical tweezer, controllable assembly and movement of microlens arrays were also realized. The results showed that an imaging system combined with droplet microlenses could image 80 nm beads under white light illumination. Using the droplet microlenses, fluorescence emission at 550 nm from CdSe@ZnS quantum dots was efficiently excited and collected. Moreover, Raman scattering signals from a silicon wafer were enhanced by ∼19 times. The presented droplet microlenses may offer new opportunities for flexible liquid devices in subwavelength imaging and detection.

中文翻译：

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使用可调和可移动液滴微透镜进行亚波长成像和检测

我们开发了由高折射率液体组成的可调和可移动液滴微透镜。通过在去离子水中超声振荡制备微透镜，微透镜的直径范围为 1 至 50 μm。通过拉伸微透镜，焦距可以从 13 到 25 μm 调整。在光镊的辅助下，还实现了微透镜阵列的可控组装和移动。结果表明，结合液滴微透镜的成像系统可以在白光照射下对 80 nm 的珠子进行成像。使用液滴微透镜，CdSe@ZnS 量子点在 550 nm 处的荧光发射被有效激发和收集。此外，来自硅晶片的拉曼散射信号增强了约 19 倍。