Sensors 2009, 9(11), 8382-8390; doi:10.3390/s91108382

Material Limitations on the Detection Limit in Refractometry

Received: 3 July 2009; in revised form: 22 September 2009 / Accepted: 29 September 2009 / Published: 26 October 2009
(This article belongs to the Special Issue Laser Spectroscopy and Sensing)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: We discuss the detection limit for refractometric sensors relying on high-Q optical cavities and show that the ultimate classical detection limit is given by min {Δn} ≳ η with n + iη being the complex refractive index of the material under refractometric investigation. Taking finite Q factors and filling fractions into account, the detection limit declines. As an example we discuss the fundamental limits of silicon-based high-Q resonators, such as photonic crystal resonators, for sensing in a bio-liquid environment, such as a water buffer. In the transparency window (λ ≳ 1100 nm) of silicon the detection limit becomes almost independent on the filling fraction, while in the visible, the detection limit depends strongly on the filling fraction because the silicon absorbs strongly.
Keywords: refractometry; resonators; optofluidics; photonic crystals
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MDPI and ACS Style

Skafte-Pedersen, P.; Nunes, P.S.; Xiao, S.; Mortensen, N.A. Material Limitations on the Detection Limit in Refractometry. Sensors 2009, 9, 8382-8390.

AMA Style

Skafte-Pedersen P, Nunes PS, Xiao S, Mortensen NA. Material Limitations on the Detection Limit in Refractometry. Sensors. 2009; 9(11):8382-8390.

Chicago/Turabian Style

Skafte-Pedersen, Peder; Nunes, Pedro S.; Xiao, Sanshui; Mortensen, Niels A. 2009. "Material Limitations on the Detection Limit in Refractometry." Sensors 9, no. 11: 8382-8390.

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