Journal article · Preprint article
Material limitations on the detection limit in refractometry
Fluidic Array Systems and Technology Group, Biomedical Micro Systems Section, Department of Micro- and Nanotechnology, Technical University of Denmark1
Biomedical Micro Systems Section, Department of Micro- and Nanotechnology, Technical University of Denmark2
Department of Micro- and Nanotechnology, Technical University of Denmark3
Structured Electromagnetic Materials, Department of Photonics Engineering, Technical University of Denmark4
Department of Photonics Engineering, Technical University of Denmark5
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.
Language: | English |
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Publisher: | Molecular Diversity Preservation International (MDPI) |
Year: | 2009 |
Pages: | 8382-8390 |
ISSN: | 14243210 and 14248220 |
Types: | Journal article and Preprint article |
DOI: | 10.3390/s91108382 |
ORCIDs: | Xiao, Sanshui and Mortensen, Asger |