Limits...
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.

Show MeSH

Related in: MedlinePlus

RCWA calculations showing differential reflectance curves for a change of the localized refractive index - 1 nm above the metallic film surface of a narrow groove gold nano-grating - from n = 1.33 to n = 1.53 upon binding of a 1nm thick target having a refractive index of 1.53 on the surface of the metallic film. The gold nano-grating had a 100 nm periodicity and the effect of nano-grating groove width ‘W’ on the differential reflectance spectra is shown for the following values of periodicity ‘P’: (a) 50 nm, (b) 100 nm, (c) 150 nm, (d) 200 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3368305&req=5

g011: RCWA calculations showing differential reflectance curves for a change of the localized refractive index - 1 nm above the metallic film surface of a narrow groove gold nano-grating - from n = 1.33 to n = 1.53 upon binding of a 1nm thick target having a refractive index of 1.53 on the surface of the metallic film. The gold nano-grating had a 100 nm periodicity and the effect of nano-grating groove width ‘W’ on the differential reflectance spectra is shown for the following values of periodicity ‘P’: (a) 50 nm, (b) 100 nm, (c) 150 nm, (d) 200 nm.

Mentions: Finally, we optimize the values of periodicity ‘P’ of the nano-gratings as well as the groove width ‘W’ to determine the maximum possible value of differential reflectance signal upon binding of a 1 nm thick target (having a refractive index of 1.53) on the surface of the metallic film. The differential reflectance signals for gold nano-gratings, having ‘W’ values varying between 3 nm and 20 nm and ‘P’ values between 50 nm and 200 nm are shown in Fig. 11Fig. 11


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

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

RCWA calculations showing differential reflectance curves for a change of the localized refractive index - 1 nm above the metallic film surface of a narrow groove gold nano-grating - from n = 1.33 to n = 1.53 upon binding of a 1nm thick target having a refractive index of 1.53 on the surface of the metallic film. The gold nano-grating had a 100 nm periodicity and the effect of nano-grating groove width ‘W’ on the differential reflectance spectra is shown for the following values of periodicity ‘P’: (a) 50 nm, (b) 100 nm, (c) 150 nm, (d) 200 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3368305&req=5

g011: RCWA calculations showing differential reflectance curves for a change of the localized refractive index - 1 nm above the metallic film surface of a narrow groove gold nano-grating - from n = 1.33 to n = 1.53 upon binding of a 1nm thick target having a refractive index of 1.53 on the surface of the metallic film. The gold nano-grating had a 100 nm periodicity and the effect of nano-grating groove width ‘W’ on the differential reflectance spectra is shown for the following values of periodicity ‘P’: (a) 50 nm, (b) 100 nm, (c) 150 nm, (d) 200 nm.
Mentions: Finally, we optimize the values of periodicity ‘P’ of the nano-gratings as well as the groove width ‘W’ to determine the maximum possible value of differential reflectance signal upon binding of a 1 nm thick target (having a refractive index of 1.53) on the surface of the metallic film. The differential reflectance signals for gold nano-gratings, having ‘W’ values varying between 3 nm and 20 nm and ‘P’ values between 50 nm and 200 nm are shown in Fig. 11Fig. 11

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