Abstract
The mathematical concept of fractals is widely applied to photonics as planar structures ranging from terahertz resonators, optical antennas, to photodetectors. Here, instead of a direct mathematical abstract, we design a plasmonic leaf with fractal geometry from the outline of a leaf from Wargrave Pink. The enhanced light-matter interactions are observed numerically from the improvement in both absorption and near-field intensification. To demonstrate the effect experimentally, a three-dimensional fractal structure is realised through direct laser writing, which significantly improves the photothermal conversion. By virtue of the self-similarity in geometry, the artificial leaf improves the absorption of a 10-nm-thick gold film with 14 × temperature increment compared to flat Au film. Not limited to the proof-of-concept photothermal experiment demonstrated here, the fractal structure with improved light-matter interactions can be utilised in a variety of applications ranging from non-linear harmonic generation, plasmonic-enhanced fluorescence, to hot electron generation for photocatalysis.
Original language | English |
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Pages (from-to) | 1291-1298 |
Number of pages | 8 |
Journal | Nanophotonics |
Volume | 8 |
Issue number | 7 |
Early online date | 29 Jun 2019 |
DOIs | |
Publication status | Published - 26 Jul 2019 |
Externally published | Yes |
Keywords
- plasmonics
- photothermal conversion
- fractal
- bio-inspired