Huang Min, Yanik Ahmet Ali, Chang Tsung-Yao, Altug Hatice
Department of Electrical and Computer Engineering, Boston University, Boston, MA 02215, USA.
Opt Express. 2009 Dec 21;17(26):24224-33. doi: 10.1364/OE.17.024224.
We introduce a novel sensor scheme combining nano-photonics and nano-fluidics on a single platform through the use of free-standing photonic crystals. By harnessing nano-scale openings, we theoretically and experimentally demonstrate that both fluidics and light can be manipulated at sub-wavelength scales. Compared to the conventional fluidic channels, we actively steer the convective flow through the nanohole openings for effective delivery of the analytes to the sensor surface. We apply our method to detect refractive index changes in aqueous solutions. Bulk measurements indicate that active delivery of the convective flow results in better sensitivities. The sensitivity of the sensor reaches 510 nm/RIU for resonance located around 850 nm with a line-width of approximately 10 nm in solution. Experimental results are matched very well with numerical simulations. We also show that cross-polarization measurements can be employed to further improve the detection limit by increasing the signal-to-noise ratio.
我们通过使用独立式光子晶体，在单个平台上引入了一种将纳米光子学和纳米流体学相结合的新型传感器方案。通过利用纳米级开口，我们在理论和实验上证明了流体和光都可以在亚波长尺度上进行操控。与传统的流体通道相比，我们通过纳米孔开口主动引导对流，以有效地将分析物输送到传感器表面。我们应用我们的方法来检测水溶液中的折射率变化。整体测量表明，对流的主动输送会带来更好的灵敏度。对于位于850nm左右的共振，传感器在溶液中的灵敏度达到510nm/RIU，线宽约为10nm。实验结果与数值模拟非常吻合。我们还表明，可以采用交叉极化测量来通过增加信噪比进一步提高检测限。
