Tunable two-dimensional liquid gradient refractive index (L-GRIN) lens for variable light focusing
Tunable two-dimensional liquid gradient refractive index (L-GRIN) lens for variable light focusing
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DOI：
10.1039/c005071g
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发表时间：
2010-01-01
期刊：
影响因子：
6.1
通讯作者：
Huang, Tony Jun
中科院分区：
文献类型：
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作者：
Huang, Hua;Mao, Xiaole;Huang, Tony Jun
我们报告了一种二维（2D）可调谐液体梯度折射率（L-GRIN）透镜，用于在面外方向上可变聚焦光。该透镜通过具有 2D 双曲正割 (HS) 折射率梯度的液体介质聚焦光束。通过具有不同折射率的两种流体（即 CaCl(2) 溶液和去离子 (DI) 水）之间的扩散，在微流体室中建立折射率梯度。通过改变 CaCl2 溶液和去离子水的流量比，可以调整 2D HS 折射率分布以及随后的 L-GRIN 透镜的焦距。通过侧视和顶视图像分析对聚焦效果进行了实验表征，实验数据与光线追踪光学模拟的结果吻合良好。 2D L-GRIN 透镜的优点包括设备制造过程简单、流体消耗率低、方便的透镜调谐机制以及与现有微流体设备的兼容性。我们预计，通过进一步优化，这款 2D L-GRIN 透镜可用于许多基于光学的芯片实验室应用。
We report a two-dimensional (2D) tunable liquid gradient refractive index (L-GRIN) lens for variable focusing of light in the out-of-plane direction. This lens focuses a light beam through a liquid medium with a 2D hyperbolic secant (HS) refractive index gradient. The refractive index gradient is established in a microfluidic chamber through the diffusion between two fluids with different refractive indices, i.e. CaCl(2) solution and deionized (DI) water. The 2D HS refractive index profile and subsequently the focal length of the L-GRIN lens can be tuned by changing the ratio of the flow rates of the CaCl2 solution and DI water. The focusing effect is experimentally characterized through side-view and top-view image analysis, and the experimental data match well with the results from ray-tracing optical simulations. Advantages of the 2D L-GRIN lens include simple device fabrication procedure, low fluid consumption rate, convenient lens-tuning mechanism, and compatibility with existing microfluidic devices. We expect that with further optimizations, this 2D L-GRIN lens can be used in many optics-based lab-on-a-chip applications.