CoChat
Sign Up
Cited by 520Plasmonic and Surface Plasmon ResearchGold and Silver Nanoparticles Synthesis and ApplicationsNear-Field Optical Microscopy

The DOI matches its Crossref record; 60 of the 60 references it cites were found in a registry or an index.

Non-plasmonic nanoantennas for surface enhanced spectroscopies with ultra-low heat conversion

Open access
Caldarola, Martín, Albella, Pablo, Cortés, Emiliano, Rahmani, Mohsen, Roschuk, Tyler, Grinblat, Gustavo, Oulton, Rupert F., Bragas, Andrea V., Maier, Stefan A.·2015·Nature Communications
DOI 10.1038/ncomms8915PMC PMC4532885
Open this paper in CoChat — free accountOpen PDF

Abstract

Nanoplasmonics has recently revolutionized our ability to control light on the nanoscale. Using metallic nanostructures with tailored shapes, it is possible to efficiently focus light into nanoscale field 'hot spots'. High field enhancement factors have been achieved in such optical nanoantennas, enabling transformative science in the areas of single molecule interactions, highly enhanced nonlinearities and nanoscale waveguiding. Unfortunately, these large enhancements come at the price of high optical losses due to absorption in the metal, severely limiting real-world applications. Via the realization of a novel nanophotonic platform based on dielectric nanostructures to form efficient nanoantennas with ultra-low light-into-heat conversion, here we demonstrate an approach that overcomes these limitations. We show that dimer-like silicon-based single nanoantennas produce both high surface enhanced fluorescence and surface enhanced Raman scattering, while at the same time generating a negligible temperature increase in their hot spots and surrounding environments.

Overview

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Integrity signals

Registry

Crossref · 10.1038/ncomms8915

Cites

60 of 60 references verified0 citation errors · 0 not checkable

Statistics

Figures

Figure 1 Design and performance of silicon nanoantennas. (a) SEM image of the array of nanostructures fabricated in Si on a silicon-on-insulator substrate. Each nanoantenna consists of two identical disks with a diameter of 220 nm, a height of 200 nm and a 20-nm gap in between. Scale bar, 2 μm. (b) SEM top-view and (c) lateral-view images of a single nanoantenna, indicated in the rectangle in a. Scale bar, 100 nm. (d) Numerical calculation results showing a scattering resonance at λ=860 nm (vertical black line) and a low absorption cross section for the Si dimer in PMMA. Note that the absorption curve is multiplied by a factor of 10. (e) Near-field distribution map for the silicon structure excited at resonance, showing good confinement of the electric field in the gap. Note that the maximum enhancement value is 5.5. Scale bar, 100 nm. (f) Experimental 2D normalized Raman map, showing enhanced signal coming from the molecules close to the nanoantennas. (g) SERS enhancement factors obtained for each individual nanoantenna shown in f, after volume normalization (see Methods, SERS mapping section, for details). The error bars show half the difference between the minimum and the maximum Raman intensity value in each nanoantenna. The dashed line corresponds to (Emax/E0)4, from e.
Figure 1 Design and performance of silicon nanoantennas. (a) SEM image of the array of nanostructures fabricated in Si on a silicon-on-insulator substrate. Each nanoantenna consists of two identical disks with a diameter of 220 nm, a height of 200 nm and a 20-nm gap in between. Scale bar, 2 μm. (b) SEM top-view and (c) lateral-view images of a single nanoantenna, indicated in the rectangle in a. Scale bar, 100 nm. (d) Numerical calculation results showing a scattering resonance at λ=860 nm (vertical black line) and a low absorption cross section for the Si dimer in PMMA. Note that the absorption curve is multiplied by a factor of 10. (e) Near-field distribution map for the silicon structure excited at resonance, showing good confinement of the electric field in the gap. Note that the maximum enhancement value is 5.5. Scale bar, 100 nm. (f) Experimental 2D normalized Raman map, showing enhanced signal coming from the molecules close to the nanoantennas. (g) SERS enhancement factors obtained for each individual nanoantenna shown in f, after volume normalization (see Methods, SERS mapping section, for details). The error bars show half the difference between the minimum and the maximum Raman intensity value in each nanoantenna. The dashed line corresponds to (Emax/E0)4, from e.CC BY · PubMed Central
Figure 2 Molecular thermometry experiment. (a) Scheme for the fluorescence imaging experiments in the nanoantenna sample. The imaging laser excites Nile Red molecules embedded in the PMMA thin-film layer on top of the nanoantennas within the confocal spot. (b) When the heating laser is turned on, the nanoantennas increase their temperature and the molecules close to the nanoantennas decrease their fluorescence emission, resulting in a lower fluorescence signal. (c) Nile Red emission spectra taken at different temperatures. The marked zone shows the detection spectral range (550–680 nm). The inset shows the integrated intensity in the detection spectral range as well as the fit used as a calibration curve to extract the corresponding temperature values.
Figure 2 Molecular thermometry experiment. (a) Scheme for the fluorescence imaging experiments in the nanoantenna sample. The imaging laser excites Nile Red molecules embedded in the PMMA thin-film layer on top of the nanoantennas within the confocal spot. (b) When the heating laser is turned on, the nanoantennas increase their temperature and the molecules close to the nanoantennas decrease their fluorescence emission, resulting in a lower fluorescence signal. (c) Nile Red emission spectra taken at different temperatures. The marked zone shows the detection spectral range (550–680 nm). The inset shows the integrated intensity in the detection spectral range as well as the fit used as a calibration curve to extract the corresponding temperature values.CC BY · PubMed Central
Figure 3 Nanoantenna fluorescence images. The top panels show SEM images of the nanoantenna arrays for reference, (a) for Si and (e) for Au. The four images below are fluorescence images corresponding to Si (left) and Au (right). Scale bar, 2 μm. Reference panels (b) and (f): fluorescence images without the heating laser turned on. (b) Silicon nanoantennas produce enhanced fluorescence while gold antennas (f) slightly enhance the fluorescence emission (see Supplementary Fig. 4 and Supplementary Note 4 for explanation). (c) and (g): Fluorescence images with the heating laser on at 6 mW μm−2. The color scale bar is the same for all the fluorescence images. Bottom panels: Intensity profiles taken from the rows indicated as lines in the fluorescence images. The intensity clearly drops for the gold antennas (h) but remains nearly constant for the silicon ones (d). The Nile Red molecules around the gold antennas are affected by drastic changes in temperature, leading to the observed intensity drop. In all the fluorescence images the background average value has been subtracted for better displaying.
Figure 3 Nanoantenna fluorescence images. The top panels show SEM images of the nanoantenna arrays for reference, (a) for Si and (e) for Au. The four images below are fluorescence images corresponding to Si (left) and Au (right). Scale bar, 2 μm. Reference panels (b) and (f): fluorescence images without the heating laser turned on. (b) Silicon nanoantennas produce enhanced fluorescence while gold antennas (f) slightly enhance the fluorescence emission (see Supplementary Fig. 4 and Supplementary Note 4 for explanation). (c) and (g): Fluorescence images with the heating laser on at 6 mW μm−2. The color scale bar is the same for all the fluorescence images. Bottom panels: Intensity profiles taken from the rows indicated as lines in the fluorescence images. The intensity clearly drops for the gold antennas (h) but remains nearly constant for the silicon ones (d). The Nile Red molecules around the gold antennas are affected by drastic changes in temperature, leading to the observed intensity drop. In all the fluorescence images the background average value has been subtracted for better displaying.CC BY · PubMed Central
Figure 4 Temperature measurement in nanoantennas. Box plot for the average temperature T, measured for (a) silicon and (b) gold nanoantennas, shown in Fig. 3, excited at resonance. It can be seen that the Au nanoantennas significantly increase their temperature when Ih increases while the Si temperature remains nearly constant. The inset in each figure shows the calculated temperature map around the disks for Ih=5 mW μm−2 in both cases. Scale bar, 100 nm. (c) Extracted temperature in the gap for selected silicon (cyan) and gold (magenta) nanoantennas as a function of the heating laser intensity at 860 nm. The dashed lines show the numerical calculations for the temperature at the gap, presenting good agreement with the experimental data. The error bars show the s.d. of the temperature measurements, obtained from error propagation from the fluorescence measurements.
Figure 4 Temperature measurement in nanoantennas. Box plot for the average temperature T, measured for (a) silicon and (b) gold nanoantennas, shown in Fig. 3, excited at resonance. It can be seen that the Au nanoantennas significantly increase their temperature when Ih increases while the Si temperature remains nearly constant. The inset in each figure shows the calculated temperature map around the disks for Ih=5 mW μm−2 in both cases. Scale bar, 100 nm. (c) Extracted temperature in the gap for selected silicon (cyan) and gold (magenta) nanoantennas as a function of the heating laser intensity at 860 nm. The dashed lines show the numerical calculations for the temperature at the gap, presenting good agreement with the experimental data. The error bars show the s.d. of the temperature measurements, obtained from error propagation from the fluorescence measurements.CC BY · PubMed Central
Figure 5 Surface enhanced fluorescence. (a) Experimental SEF map obtained for the Si antennas. It can be clearly seen that fluorescence is enhanced over the antennas. (b) SEF enhancement factor (FSEF) obtained from the maximum values over each antenna in a, calculated in similar way as FSERS. The error bars show half the difference between the minimum and the maximum value in each nanoantenna.
Figure 5 Surface enhanced fluorescence. (a) Experimental SEF map obtained for the Si antennas. It can be clearly seen that fluorescence is enhanced over the antennas. (b) SEF enhancement factor (FSEF) obtained from the maximum values over each antenna in a, calculated in similar way as FSERS. The error bars show half the difference between the minimum and the maximum value in each nanoantenna.CC BY · PubMed Central

Verification

Claims the paper makes

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

The self-check needs the paper’s full text.

Citations

Cites

Show all 60 references

Cited by

Sorted by citations

Related

See all

Metadata

Authors
Caldarola, M., Albella, P., Cortés, E., Rahmani, M., Roschuk, T., Grinblat, G., Oulton, R. F., Bragas, A. V., & Maier, S. A.
Affiliations
  • Consejo Nacional de Investigaciones Científicas y Técnicas (AR)
  • Imperial College London (GB)
Corresponding author
  • Bragas, Andrea V.
  • Maier, Stefan A.
ORCID
Venue
Nature Communications
Publisher
Springer Science and Business Media LLC
Published
2015-08-04
Volume
6
Issue
1
Pages
7915-7915
ISSN
2041-1723 (ISSN-L)
DOI
10.1038/ncomms8915
PMC
PMC4532885
OpenAlex
W2254159412
Cited by
520
References
60
Citations by year
2026: 16 · 2025: 22 · 2024: 36 · 2023: 35 · 2022: 41 · 2021: 47 · 2020: 59 · 2019: 70 · 2018: 73 · 2017: 64 · 2016: 51 · 2015: 5
FWCI
32.00
Type
journal article
Language
en
Open access
Licence
Locations
  • Nature Communications (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Leiden Repository (Leiden University) (submittedVersion)
  • Spiral (Imperial College London) (submittedVersion)
  • RePEc: Research Papers in Economics (submittedVersion)
  • Americanae (AECID Library) (submittedVersion, cc-by-nc-sa)
  • UCrea (University of Cantabria) (submittedVersion, cc-by)
  • LA Referencia (Red Federada de Repositorios Institucionales de Publicaciones Científicas) (submittedVersion, cc-by-nc-sa)
  • Data Archiving and Networked Services (DANS) (submittedVersion, other-oa)
  • Greater South Information System
Funders
  • Leverhulme Trust
  • Universidad de Buenos Aires (2014‐2017)
  • Engineering and Physical Sciences Research Council (EP/I004343/1, EP/H000917/2, EP/H000844/1)
  • Agencia Nacional de Promoción Científica y Tecnológica (2010-00825)
  • Office of Naval Research
  • Office of Naval Research Global
Topics
  • Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Plasmonic and Surface Plasmon Research
  • Physical Sciences › Materials Science › Electronic, Optical and Magnetic Materials › Gold and Silver Nanoparticles Synthesis and Applications
  • Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Near-Field Optical Microscopy
Keywords
dielectric nanostructures, silicon nanoantennas, surface-enhanced fluorescence, surface-enhanced Raman scattering, optical loss, heat generation, hot spots, nanophotonics

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review