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- Xu, Tao, et al.
(författare)
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Silicon-on-insulator nanopillar-array optical sensor
- 2011
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Ingår i: Progress in Biomedical Optics and Imaging - Proceedings of SPIE. - : SPIE - International Society for Optical Engineering. - 9780819484451
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Konferensbidrag (refereegranskat)abstract
- Pillar-array based optical cavities have unique properties, e.g., having a large and connected low dielectric index space (normally air space), having a large percent of electric field energy in air and standing on a substrate. These properties make them well suitable to make ultra compact and highly sensitive label-free optical sensors to detect bio-/chemical reactions. We designed, fabricated, and measured a silicon-on-insulator pillar array microcavity that possesses a quality factor as high as 27,600. We studied its sensitivity for both bulk index change and surface index modification. As a bulk index sensor, for environmental refractive index change of 0.01, a resonance peak wavelength shift of 3.5 nm was measured. As a surface index sensor, the simulations show, for a coating with thickness of 1 nm, the resonance wavelength shifts as large as 2.86 nm. Combining with a sharp 0.06 nm wide resonance peak, our pillar-array sensor is able to resolve ultra small bulk and surface refractive index changes caused by target molecules.
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