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Proceedings Paper

Integration of sub-wavelength nanofluidics on suspended photonic crystal sensors
Author(s): Min Huang; Ahmet Ali Yanik; Tsung-Yao Chang; Hatice Altug
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Paper Abstract

In this paper, we introduce a novel sensor scheme which merges nano-photonics and nano-fluidics on a single platform through the use of free-standing photonic crystals (PhCs). PhCs offer great freedom to manipulate the spatial extent and the spectral characteristics of the electromagnetic fields. Also, nanoholes in PhCs provide a natural platform to transport solutions. By harnessing these nano-scale openings, we theoretically and experimentally demonstrate that both fluidics and light can be manipulated at sub-wavelength scales. In this scheme, the free standing PhCs are sealed in a chamber such that only the nano-scale hole arrays enable the flow between the top and the bottom channels. The nanohole arrays are used as sensing structures as well as nanofluidic channels. Compared to the conventional fluidic channels, we can actively steer the convective flow through the nanohole openings for effective delivery of the analytes to the sensor surface. This scheme also helps to overcome the surface tension of highly viscous solution and guarantees that the sensor can be totally immersed in solution. We apply this method to detect refractive index changes in aqueous solutions. Bulk measurements indicate that active delivery of the convective flow results in better performance. The sensitivity of the sensor reaches 510 nm/RIU for resonance located around 850 nm with a line-width of ~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.

Paper Details

Date Published: 27 August 2010
PDF: 6 pages
Proc. SPIE 7762, Optical Trapping and Optical Micromanipulation VII, 77621Y (27 August 2010); doi: 10.1117/12.860793
Show Author Affiliations
Min Huang, Boston Univ. (United States)
Ahmet Ali Yanik, Boston Univ. (United States)
Tsung-Yao Chang, Massachusetts Institute of Technology (United States)
Hatice Altug, Boston Univ. (United States)

Published in SPIE Proceedings Vol. 7762:
Optical Trapping and Optical Micromanipulation VII
Kishan Dholakia; Gabriel C. Spalding, Editor(s)

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