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Evanescent field Sensors Based on Tantalum Pentoxide Waveguides – A Review

View Article: PubMed Central - PubMed

ABSTRACT

Evanescent field sensors based on waveguide surfaces play an important role where high sensitivity is required. Particularly tantalum pentoxide (Ta2O5) is a suitable material for thin-film waveguides due to its high refractive index and low attenuation. Many label-free biosensor systems such as grating couplers and interferometric sensors as well as fluorescence-based systems benefit from this waveguide material leading to extremely high sensitivity. Some biosensor systems based on Ta2O5 waveguides already took the step into commercialization. This report reviews the various detection systems in terms of limit of detection, the applications, and the suitable surface chemistry.

No MeSH data available.


Theoretical sensitivities of a waveguide to a) cover refractive index changes and b) surface adlayer changes versus waveguide thickness. Parameters for calculation: ns = 1.52, nw = 2.1, nc = 1.333 and λ = 675 nm. From [21].
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f4-sensors-08-00711: Theoretical sensitivities of a waveguide to a) cover refractive index changes and b) surface adlayer changes versus waveguide thickness. Parameters for calculation: ns = 1.52, nw = 2.1, nc = 1.333 and λ = 675 nm. From [21].

Mentions: Figure 4 shows the sensitivities and versus waveguide thickness for the first two TE-and TM modes (0 and 1). It can be seen that TM modes yield higher sensitivities for the given parameters and that a waveguide thickness of 150-160 nm should be optimal for TM.


Evanescent field Sensors Based on Tantalum Pentoxide Waveguides – A Review
Theoretical sensitivities of a waveguide to a) cover refractive index changes and b) surface adlayer changes versus waveguide thickness. Parameters for calculation: ns = 1.52, nw = 2.1, nc = 1.333 and λ = 675 nm. From [21].
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3927514&req=5

f4-sensors-08-00711: Theoretical sensitivities of a waveguide to a) cover refractive index changes and b) surface adlayer changes versus waveguide thickness. Parameters for calculation: ns = 1.52, nw = 2.1, nc = 1.333 and λ = 675 nm. From [21].
Mentions: Figure 4 shows the sensitivities and versus waveguide thickness for the first two TE-and TM modes (0 and 1). It can be seen that TM modes yield higher sensitivities for the given parameters and that a waveguide thickness of 150-160 nm should be optimal for TM.

View Article: PubMed Central - PubMed

ABSTRACT

Evanescent field sensors based on waveguide surfaces play an important role where high sensitivity is required. Particularly tantalum pentoxide (Ta2O5) is a suitable material for thin-film waveguides due to its high refractive index and low attenuation. Many label-free biosensor systems such as grating couplers and interferometric sensors as well as fluorescence-based systems benefit from this waveguide material leading to extremely high sensitivity. Some biosensor systems based on Ta2O5 waveguides already took the step into commercialization. This report reviews the various detection systems in terms of limit of detection, the applications, and the suitable surface chemistry.

No MeSH data available.