Details
| Original language | English |
|---|---|
| Pages (from-to) | 4779-4786 |
| Number of pages | 8 |
| Journal | Nano Letters |
| Volume | 19 |
| Issue number | 7 |
| Publication status | Published - 17 Jun 2019 |
Abstract
We experimentally investigate the interaction between hybrid-morphology gold optical antennas and a few-cycle Ti:sapphire laser up to ablative intensities, demonstrating rich nonlinear plasmonic effects and promising applications in coherent frequency upconversion and nanofabrication technology. The two-dimensional array of hybrid antennas consists of elliptical apertures combined with bowties in its minor axis. The plasmonic resonance frequency of the bowties is red-shifted with respect to the laser central frequency and thus mainly enhances the third harmonic spectrum at long wavelengths. The gold film between two neighboring elliptical apertures forms an hourglass-shaped structure, which acts as a "plasmonic lens" and thus strongly reinforces surface currents into a small area. This enhanced surface current produces a rotating magnetic field that deeply penetrates into the substrate. At resonant frequency, the magnetic field is further intensified by the bowties. The resonant frequency of the hourglass is blueshifted with respect to the laser central frequency. Consequently, it spectacularly extends the third harmonic spectrum toward short wavelengths. The resultant third harmonic signal ranges from 230 to 300 nm, much broader than the emission from a sapphire crystal. In addition, the concentration of surface current within the neck of the hourglass antenna results in a structural modification through laser ablation, producing sub-10 nm sharp metallic gaps. Moreover, after laser illumination the optical field hotspots are imprinted around the antennas, allowing us to confirm the subwavelength enhancement of the electric near-field intensity.
Keywords
- broadband deep-ultraviolet, laser ablation, nanoscale gaps, near-field mapping, Nonlinear plasmonics
ASJC Scopus subject areas
- Chemical Engineering(all)
- Bioengineering
- Chemistry(all)
- General Chemistry
- Materials Science(all)
- General Materials Science
- Physics and Astronomy(all)
- Condensed Matter Physics
- Engineering(all)
- Mechanical Engineering
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In: Nano Letters, Vol. 19, No. 7, 17.06.2019, p. 4779-4786.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Generating Ultrabroadband Deep-UV Radiation and Sub-10 nm Gap by Hybrid-Morphology Gold Antennas
AU - Shi, Liping
AU - Cardoso de Andrade, José Ricardo
AU - Tajalli Seifi, Ayhan
AU - Geng, Jiao
AU - Yi, Juemin
AU - Heidenblut, Torsten
AU - Segerink, Frans B.
AU - Babushkin, Ihar
AU - Kholodtsova, Maria
AU - Merdji, Hamed
AU - Bastiaens, Bert
AU - Morgner, Uwe
AU - Kovacev, Milutin
N1 - The authors thank funding supports from Deutsche Forschungsgemeinschaft (DFG) (KO 3798/4-1) and from German Research Foundation under Germany’s Excellence Strategy EXC-2123 and Germany’s Excellence Strategy within the Cluster of Excellence PhoenixD (EXC 2122, Project ID 390833453), Lower Saxony through “Quanten und Nanometrologie” (QUANOMET, Project Nanophotonik). H.M. acknowledges support from the PETACom FET Open H2020, support from the French ministry of research through the ANR grants 2014 “IPEX”, 2017 “PACHA”, the DGA RAPID grant “SWIM”, the LABEX “PALM” (ANR-10-LABX-0039-PALM) through he grants “Plasmon-X”, “STAMPS”, and “HILAC”. We acknowledge financial support from the French ASTRE program through the “NanoLight” grant.
PY - 2019/6/17
Y1 - 2019/6/17
N2 - We experimentally investigate the interaction between hybrid-morphology gold optical antennas and a few-cycle Ti:sapphire laser up to ablative intensities, demonstrating rich nonlinear plasmonic effects and promising applications in coherent frequency upconversion and nanofabrication technology. The two-dimensional array of hybrid antennas consists of elliptical apertures combined with bowties in its minor axis. The plasmonic resonance frequency of the bowties is red-shifted with respect to the laser central frequency and thus mainly enhances the third harmonic spectrum at long wavelengths. The gold film between two neighboring elliptical apertures forms an hourglass-shaped structure, which acts as a "plasmonic lens" and thus strongly reinforces surface currents into a small area. This enhanced surface current produces a rotating magnetic field that deeply penetrates into the substrate. At resonant frequency, the magnetic field is further intensified by the bowties. The resonant frequency of the hourglass is blueshifted with respect to the laser central frequency. Consequently, it spectacularly extends the third harmonic spectrum toward short wavelengths. The resultant third harmonic signal ranges from 230 to 300 nm, much broader than the emission from a sapphire crystal. In addition, the concentration of surface current within the neck of the hourglass antenna results in a structural modification through laser ablation, producing sub-10 nm sharp metallic gaps. Moreover, after laser illumination the optical field hotspots are imprinted around the antennas, allowing us to confirm the subwavelength enhancement of the electric near-field intensity.
AB - We experimentally investigate the interaction between hybrid-morphology gold optical antennas and a few-cycle Ti:sapphire laser up to ablative intensities, demonstrating rich nonlinear plasmonic effects and promising applications in coherent frequency upconversion and nanofabrication technology. The two-dimensional array of hybrid antennas consists of elliptical apertures combined with bowties in its minor axis. The plasmonic resonance frequency of the bowties is red-shifted with respect to the laser central frequency and thus mainly enhances the third harmonic spectrum at long wavelengths. The gold film between two neighboring elliptical apertures forms an hourglass-shaped structure, which acts as a "plasmonic lens" and thus strongly reinforces surface currents into a small area. This enhanced surface current produces a rotating magnetic field that deeply penetrates into the substrate. At resonant frequency, the magnetic field is further intensified by the bowties. The resonant frequency of the hourglass is blueshifted with respect to the laser central frequency. Consequently, it spectacularly extends the third harmonic spectrum toward short wavelengths. The resultant third harmonic signal ranges from 230 to 300 nm, much broader than the emission from a sapphire crystal. In addition, the concentration of surface current within the neck of the hourglass antenna results in a structural modification through laser ablation, producing sub-10 nm sharp metallic gaps. Moreover, after laser illumination the optical field hotspots are imprinted around the antennas, allowing us to confirm the subwavelength enhancement of the electric near-field intensity.
KW - broadband deep-ultraviolet
KW - laser ablation
KW - nanoscale gaps
KW - near-field mapping
KW - Nonlinear plasmonics
UR - http://www.scopus.com/inward/record.url?scp=85068112397&partnerID=8YFLogxK
U2 - 10.1021/acs.nanolett.9b02100
DO - 10.1021/acs.nanolett.9b02100
M3 - Article
C2 - 31244236
AN - SCOPUS:85068112397
VL - 19
SP - 4779
EP - 4786
JO - Nano Letters
JF - Nano Letters
SN - 1530-6984
IS - 7
ER -