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Narrow groove plasmonic nano-gratings for surface plasmon resonance sensing.

Dhawan A, Canva M, Vo-Dinh T - Opt Express (2011)

Bottom Line: We present a novel surface plasmon resonance (SPR) configuration based on narrow groove (sub-15 nm) plasmonic nano-gratings such that normally incident radiation can be coupled into surface plasmons without the use of prism-coupling based total internal reflection, as in the classical Kretschmann configuration.Our calculations indicate substantially higher differential reflectance signals, on localized change of refractive index in the narrow groove plasmonic gratings, as compared to those obtained from conventional SPR-based sensing systems.Furthermore, these calculations allow determination of the optimal nano-grating geometric parameters - i. e. nanoline periodicity, spacing between the nanolines, as well as the height of the nanolines in the nano-grating - for highest sensitivity to localized change of refractive index, as would occur due to binding of a biomolecule target to a functionalized nano-grating surface.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA.

ABSTRACT
We present a novel surface plasmon resonance (SPR) configuration based on narrow groove (sub-15 nm) plasmonic nano-gratings such that normally incident radiation can be coupled into surface plasmons without the use of prism-coupling based total internal reflection, as in the classical Kretschmann configuration. This eliminates the angular dependence requirements of SPR-based sensing and allows development of robust miniaturized SPR sensors. Simulations based on Rigorous Coupled Wave Analysis (RCWA) were carried out to numerically calculate the reflectance - from different gold and silver nano-grating structures - as a function of the localized refractive index of the media around the SPR nano-gratings as well as the incident radiation wavelength and angle of incidence. Our calculations indicate substantially higher differential reflectance signals, on localized change of refractive index in the narrow groove plasmonic gratings, as compared to those obtained from conventional SPR-based sensing systems. Furthermore, these calculations allow determination of the optimal nano-grating geometric parameters - i. e. nanoline periodicity, spacing between the nanolines, as well as the height of the nanolines in the nano-grating - for highest sensitivity to localized change of refractive index, as would occur due to binding of a biomolecule target to a functionalized nano-grating surface.

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RCWA calculations showing the effect of groove width ā€˜Wā€™ on the amplitude of the differential reflectance (peak maxima ā€“ peak minima) signals obtained from silver nano-gratings, when the plasmon resonance related dips in the reflectance spectra (before and after the localized refractive index change) - as well as the maxima and the minima in the differential reflectance curves - are considered (a) for wavelengths less than 1600 nm and (b) for wavelengths less than 800 nm. The silver nano-grating had a 100 nm periodicity and the effect of nano-grating groove width ā€˜Wā€™ on the differential reflectance amplitude is plotted for different values of periodicity ā€˜Pā€™: 50 nm (continuous light green line), 100 nm (continuous red line), 150 nm (continuous dark green line), and 200 nm (continuous blue line). The differential reflectance curves were obtained for a change of the localized refractive index - 1 nm above the metallic film surface of a narrow groove silver nano-grating - from n = 1.33 to n = 1.53 upon binding of a 1 nm thick target having a refractive index of 1.53 on the surface of the metallic film. The dashed black line provides the baseline value of the amplitude of differential reflectance for a planar silver film evaluated using the Kretschmann configuration and employing wavelength interrogation. The other dashed lines provide the baseline values of the amplitude of differential reflectance for a planar silver film - evaluated using Kretschmann configuration and employing wavelength interrogation - that are normalized such that the planar silver film would have equivalent surface area as would be present in silver nano-gratings of groove periodicity ā€˜Pā€™ when the value of ā€˜Pā€™ is 50 nm (dashed light green line), 100 nm (dashed red line), 150 nm (dashed dark green line), and 200 nm (dashed blue line).
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g014: RCWA calculations showing the effect of groove width ā€˜Wā€™ on the amplitude of the differential reflectance (peak maxima ā€“ peak minima) signals obtained from silver nano-gratings, when the plasmon resonance related dips in the reflectance spectra (before and after the localized refractive index change) - as well as the maxima and the minima in the differential reflectance curves - are considered (a) for wavelengths less than 1600 nm and (b) for wavelengths less than 800 nm. The silver nano-grating had a 100 nm periodicity and the effect of nano-grating groove width ā€˜Wā€™ on the differential reflectance amplitude is plotted for different values of periodicity ā€˜Pā€™: 50 nm (continuous light green line), 100 nm (continuous red line), 150 nm (continuous dark green line), and 200 nm (continuous blue line). The differential reflectance curves were obtained for a change of the localized refractive index - 1 nm above the metallic film surface of a narrow groove silver nano-grating - from n = 1.33 to n = 1.53 upon binding of a 1 nm thick target having a refractive index of 1.53 on the surface of the metallic film. The dashed black line provides the baseline value of the amplitude of differential reflectance for a planar silver film evaluated using the Kretschmann configuration and employing wavelength interrogation. The other dashed lines provide the baseline values of the amplitude of differential reflectance for a planar silver film - evaluated using Kretschmann configuration and employing wavelength interrogation - that are normalized such that the planar silver film would have equivalent surface area as would be present in silver nano-gratings of groove periodicity ā€˜Pā€™ when the value of ā€˜Pā€™ is 50 nm (dashed light green line), 100 nm (dashed red line), 150 nm (dashed dark green line), and 200 nm (dashed blue line).

Mentions: Figure 14Fig. 14


Narrow groove plasmonic nano-gratings for surface plasmon resonance sensing.

Dhawan A, Canva M, Vo-Dinh T - Opt Express (2011)

RCWA calculations showing the effect of groove width ā€˜Wā€™ on the amplitude of the differential reflectance (peak maxima ā€“ peak minima) signals obtained from silver nano-gratings, when the plasmon resonance related dips in the reflectance spectra (before and after the localized refractive index change) - as well as the maxima and the minima in the differential reflectance curves - are considered (a) for wavelengths less than 1600 nm and (b) for wavelengths less than 800 nm. The silver nano-grating had a 100 nm periodicity and the effect of nano-grating groove width ā€˜Wā€™ on the differential reflectance amplitude is plotted for different values of periodicity ā€˜Pā€™: 50 nm (continuous light green line), 100 nm (continuous red line), 150 nm (continuous dark green line), and 200 nm (continuous blue line). The differential reflectance curves were obtained for a change of the localized refractive index - 1 nm above the metallic film surface of a narrow groove silver nano-grating - from n = 1.33 to n = 1.53 upon binding of a 1 nm thick target having a refractive index of 1.53 on the surface of the metallic film. The dashed black line provides the baseline value of the amplitude of differential reflectance for a planar silver film evaluated using the Kretschmann configuration and employing wavelength interrogation. The other dashed lines provide the baseline values of the amplitude of differential reflectance for a planar silver film - evaluated using Kretschmann configuration and employing wavelength interrogation - that are normalized such that the planar silver film would have equivalent surface area as would be present in silver nano-gratings of groove periodicity ā€˜Pā€™ when the value of ā€˜Pā€™ is 50 nm (dashed light green line), 100 nm (dashed red line), 150 nm (dashed dark green line), and 200 nm (dashed blue line).
© Copyright Policy - open-access
Related In: Results  -  Collection

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g014: RCWA calculations showing the effect of groove width ā€˜Wā€™ on the amplitude of the differential reflectance (peak maxima ā€“ peak minima) signals obtained from silver nano-gratings, when the plasmon resonance related dips in the reflectance spectra (before and after the localized refractive index change) - as well as the maxima and the minima in the differential reflectance curves - are considered (a) for wavelengths less than 1600 nm and (b) for wavelengths less than 800 nm. The silver nano-grating had a 100 nm periodicity and the effect of nano-grating groove width ā€˜Wā€™ on the differential reflectance amplitude is plotted for different values of periodicity ā€˜Pā€™: 50 nm (continuous light green line), 100 nm (continuous red line), 150 nm (continuous dark green line), and 200 nm (continuous blue line). The differential reflectance curves were obtained for a change of the localized refractive index - 1 nm above the metallic film surface of a narrow groove silver nano-grating - from n = 1.33 to n = 1.53 upon binding of a 1 nm thick target having a refractive index of 1.53 on the surface of the metallic film. The dashed black line provides the baseline value of the amplitude of differential reflectance for a planar silver film evaluated using the Kretschmann configuration and employing wavelength interrogation. The other dashed lines provide the baseline values of the amplitude of differential reflectance for a planar silver film - evaluated using Kretschmann configuration and employing wavelength interrogation - that are normalized such that the planar silver film would have equivalent surface area as would be present in silver nano-gratings of groove periodicity ā€˜Pā€™ when the value of ā€˜Pā€™ is 50 nm (dashed light green line), 100 nm (dashed red line), 150 nm (dashed dark green line), and 200 nm (dashed blue line).
Mentions: Figure 14Fig. 14

Bottom Line: We present a novel surface plasmon resonance (SPR) configuration based on narrow groove (sub-15 nm) plasmonic nano-gratings such that normally incident radiation can be coupled into surface plasmons without the use of prism-coupling based total internal reflection, as in the classical Kretschmann configuration.Our calculations indicate substantially higher differential reflectance signals, on localized change of refractive index in the narrow groove plasmonic gratings, as compared to those obtained from conventional SPR-based sensing systems.Furthermore, these calculations allow determination of the optimal nano-grating geometric parameters - i. e. nanoline periodicity, spacing between the nanolines, as well as the height of the nanolines in the nano-grating - for highest sensitivity to localized change of refractive index, as would occur due to binding of a biomolecule target to a functionalized nano-grating surface.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA.

ABSTRACT
We present a novel surface plasmon resonance (SPR) configuration based on narrow groove (sub-15 nm) plasmonic nano-gratings such that normally incident radiation can be coupled into surface plasmons without the use of prism-coupling based total internal reflection, as in the classical Kretschmann configuration. This eliminates the angular dependence requirements of SPR-based sensing and allows development of robust miniaturized SPR sensors. Simulations based on Rigorous Coupled Wave Analysis (RCWA) were carried out to numerically calculate the reflectance - from different gold and silver nano-grating structures - as a function of the localized refractive index of the media around the SPR nano-gratings as well as the incident radiation wavelength and angle of incidence. Our calculations indicate substantially higher differential reflectance signals, on localized change of refractive index in the narrow groove plasmonic gratings, as compared to those obtained from conventional SPR-based sensing systems. Furthermore, these calculations allow determination of the optimal nano-grating geometric parameters - i. e. nanoline periodicity, spacing between the nanolines, as well as the height of the nanolines in the nano-grating - for highest sensitivity to localized change of refractive index, as would occur due to binding of a biomolecule target to a functionalized nano-grating surface.

Show MeSH
Related in: MedlinePlus