Limits...
Oscillatory penetration of near-fields in plasmonic excitation at metal-dielectric interfaces.

Lee SC, Kang JH, Park QH, Krishna S, Brueck SR - Sci Rep (2016)

Bottom Line: This unusual field penetration is explained by the interference between these contributions, and is experimentally confirmed through an aperture which is engineered with four arms stretched out from a simple circle to manipulate a specific plasmonic excitation available in the metal film.A numerical simulation quantitatively supports the experiment.This fundamental characteristic will impact plasmonics with the near-fields designed by aperture engineering for practical applications.

View Article: PubMed Central - PubMed

Affiliation: Center for High Technology Materials and Department of Electrical and Computer Engineering, University of New Mexico, Albuquerque, NM 87106, USA.

ABSTRACT
The electric field immediately below an illuminated metal-film that is perforated with a hole array on a dielectric consists of direct transmission and scattering of the incident light through the holes and evanescent near-field from plasmonic excitations. Depending on the size and shape of the hole apertures, it exhibits an oscillatory decay in the propagation direction. This unusual field penetration is explained by the interference between these contributions, and is experimentally confirmed through an aperture which is engineered with four arms stretched out from a simple circle to manipulate a specific plasmonic excitation available in the metal film. A numerical simulation quantitatively supports the experiment. This fundamental characteristic will impact plasmonics with the near-fields designed by aperture engineering for practical applications.

No MeSH data available.


Related in: MedlinePlus

Simulation of NFI with a CX aperture MPC.(a) The hole shape used in the FDTD simulation that is similar to Fig. 3b. (b) A plot of absorption vs. wavelength of CX MPC with the aperture in (a) from the simulation along the variation of κA from 0 to 0.3. The brown arrow indicates the splitting in SR1. 3D maps of /Ez,MPC/ at (c) SR1, (d) SR2, and (e) 8.3 μm of an MPC with CX of (a) in xy- (z = −0.565 μm) and zx plane (−4.6 μm ≤ z ≤ 0) for κA = 0.03. The side-view is along the black dashed line in (a). The dashed shape on the xy plane is the projection of the CX at the top. (f) Depth profile of /Ez,MPC/ vs z at the edge of the CX aperture indicated with dashed color lines in (c–e). The dotted black lines across the side views are the layer interfaces shown in Fig. 2d, matching (c–f) in z. The dashed line on the red curve in (f) is the fitting segment used for δ in (2). A shaded region in (f) indicates the absorber. The orange dashed lines follow z = −0.565 μm in the middle of the absorber where the splitting of the zx-side view occurs to reveal the xy-plan view at the given z in the field map. The incident light is polarized along the x-axis.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4835736&req=5

f4: Simulation of NFI with a CX aperture MPC.(a) The hole shape used in the FDTD simulation that is similar to Fig. 3b. (b) A plot of absorption vs. wavelength of CX MPC with the aperture in (a) from the simulation along the variation of κA from 0 to 0.3. The brown arrow indicates the splitting in SR1. 3D maps of /Ez,MPC/ at (c) SR1, (d) SR2, and (e) 8.3 μm of an MPC with CX of (a) in xy- (z = −0.565 μm) and zx plane (−4.6 μm ≤ z ≤ 0) for κA = 0.03. The side-view is along the black dashed line in (a). The dashed shape on the xy plane is the projection of the CX at the top. (f) Depth profile of /Ez,MPC/ vs z at the edge of the CX aperture indicated with dashed color lines in (c–e). The dotted black lines across the side views are the layer interfaces shown in Fig. 2d, matching (c–f) in z. The dashed line on the red curve in (f) is the fitting segment used for δ in (2). A shaded region in (f) indicates the absorber. The orange dashed lines follow z = −0.565 μm in the middle of the absorber where the splitting of the zx-side view occurs to reveal the xy-plan view at the given z in the field map. The incident light is polarized along the x-axis.

Mentions: The structure in Fig. 4a, imitating the CX shape of Fig. 3b, was used for FDTD simulation. This aperture has the same opening area as the medium circle with the same maximum lateral dimension as the large circle. Figure 4b shows the simulated total absorption spectra with κA scaled from 0 to 0.3 at 10 μm. As indicated by arrows in the figure, SR1 and SR2 are around 10.6 μm (=) and 7.3 μm (=) for κA = 0.03 which are only slightly different from λSR1 and λSR2 experimentally observed for the CX device in Fig. 3d. The material parameters assumed in the simulation could be a reason for this minor difference. The absorption of SR1 at λSR1 increases with κA as expected. SR1 shows a splitting similar to that noticed experimentally in Fig. 3d. Another peak at ~8.3 μm appears in Fig. 4b as was observed in connection with Fig. 2a. This peak does not contribute to the photoresponse, as discussed later.


Oscillatory penetration of near-fields in plasmonic excitation at metal-dielectric interfaces.

Lee SC, Kang JH, Park QH, Krishna S, Brueck SR - Sci Rep (2016)

Simulation of NFI with a CX aperture MPC.(a) The hole shape used in the FDTD simulation that is similar to Fig. 3b. (b) A plot of absorption vs. wavelength of CX MPC with the aperture in (a) from the simulation along the variation of κA from 0 to 0.3. The brown arrow indicates the splitting in SR1. 3D maps of /Ez,MPC/ at (c) SR1, (d) SR2, and (e) 8.3 μm of an MPC with CX of (a) in xy- (z = −0.565 μm) and zx plane (−4.6 μm ≤ z ≤ 0) for κA = 0.03. The side-view is along the black dashed line in (a). The dashed shape on the xy plane is the projection of the CX at the top. (f) Depth profile of /Ez,MPC/ vs z at the edge of the CX aperture indicated with dashed color lines in (c–e). The dotted black lines across the side views are the layer interfaces shown in Fig. 2d, matching (c–f) in z. The dashed line on the red curve in (f) is the fitting segment used for δ in (2). A shaded region in (f) indicates the absorber. The orange dashed lines follow z = −0.565 μm in the middle of the absorber where the splitting of the zx-side view occurs to reveal the xy-plan view at the given z in the field map. The incident light is polarized along the x-axis.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835736&req=5

f4: Simulation of NFI with a CX aperture MPC.(a) The hole shape used in the FDTD simulation that is similar to Fig. 3b. (b) A plot of absorption vs. wavelength of CX MPC with the aperture in (a) from the simulation along the variation of κA from 0 to 0.3. The brown arrow indicates the splitting in SR1. 3D maps of /Ez,MPC/ at (c) SR1, (d) SR2, and (e) 8.3 μm of an MPC with CX of (a) in xy- (z = −0.565 μm) and zx plane (−4.6 μm ≤ z ≤ 0) for κA = 0.03. The side-view is along the black dashed line in (a). The dashed shape on the xy plane is the projection of the CX at the top. (f) Depth profile of /Ez,MPC/ vs z at the edge of the CX aperture indicated with dashed color lines in (c–e). The dotted black lines across the side views are the layer interfaces shown in Fig. 2d, matching (c–f) in z. The dashed line on the red curve in (f) is the fitting segment used for δ in (2). A shaded region in (f) indicates the absorber. The orange dashed lines follow z = −0.565 μm in the middle of the absorber where the splitting of the zx-side view occurs to reveal the xy-plan view at the given z in the field map. The incident light is polarized along the x-axis.
Mentions: The structure in Fig. 4a, imitating the CX shape of Fig. 3b, was used for FDTD simulation. This aperture has the same opening area as the medium circle with the same maximum lateral dimension as the large circle. Figure 4b shows the simulated total absorption spectra with κA scaled from 0 to 0.3 at 10 μm. As indicated by arrows in the figure, SR1 and SR2 are around 10.6 μm (=) and 7.3 μm (=) for κA = 0.03 which are only slightly different from λSR1 and λSR2 experimentally observed for the CX device in Fig. 3d. The material parameters assumed in the simulation could be a reason for this minor difference. The absorption of SR1 at λSR1 increases with κA as expected. SR1 shows a splitting similar to that noticed experimentally in Fig. 3d. Another peak at ~8.3 μm appears in Fig. 4b as was observed in connection with Fig. 2a. This peak does not contribute to the photoresponse, as discussed later.

Bottom Line: This unusual field penetration is explained by the interference between these contributions, and is experimentally confirmed through an aperture which is engineered with four arms stretched out from a simple circle to manipulate a specific plasmonic excitation available in the metal film.A numerical simulation quantitatively supports the experiment.This fundamental characteristic will impact plasmonics with the near-fields designed by aperture engineering for practical applications.

View Article: PubMed Central - PubMed

Affiliation: Center for High Technology Materials and Department of Electrical and Computer Engineering, University of New Mexico, Albuquerque, NM 87106, USA.

ABSTRACT
The electric field immediately below an illuminated metal-film that is perforated with a hole array on a dielectric consists of direct transmission and scattering of the incident light through the holes and evanescent near-field from plasmonic excitations. Depending on the size and shape of the hole apertures, it exhibits an oscillatory decay in the propagation direction. This unusual field penetration is explained by the interference between these contributions, and is experimentally confirmed through an aperture which is engineered with four arms stretched out from a simple circle to manipulate a specific plasmonic excitation available in the metal film. A numerical simulation quantitatively supports the experiment. This fundamental characteristic will impact plasmonics with the near-fields designed by aperture engineering for practical applications.

No MeSH data available.


Related in: MedlinePlus