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5High-Q IR plasmonic platforms produced by direct femtosecond
laser printing
D. Pavlov1, A. Kuchmizhak1'2*
1-Institute of Automation and Control Processes, Far Eastern Branch of RAS, Vladivostok, 690041 Russia 2- Far Eastern Federal University, 690090 Vladivostok, Russia
Proper arrangement of the plasmonic nanostructures into well-ordered arrays opens up pathways for excitation of collective resonance characterized by high Q-factors and strong light localization that is important for diverse applications including light-matter interaction, nonlinear optics and sensing. Excitation of so-called quasi-bound states in the continuum (q-BIC) in plasmonic nanostructures has recently gained substantial research interest, yet fabrication of such sophisticated nanostructure arrangement still relies on the expensive and time-consuming lithography-based approaches. In this presentation, the possibility of using direct femtosecond laser printing of specific nanostructure arrays supporting q-BICs will be discussed. The developed approach is based on rather unique thermo-mechanical behaviour of the gold film subjected to the exposure of nJ-energy laser pulse resulting in its ultrafast melting, local relaxation from the supporting substrate and recrystallization in the form of hollow-shape nano-cavities referred to as nanobumps or nanojets [1]. The process is highly controllable reflecting the ablation-free character of the laser patterning process (Figure 1). We showed that nanobumps and nanojets arranged into a square and hexagonal lattice supports the high-Q plasmonic modes resulting from coupling and destructive interference of the plasmonic waves. Existence of such modes were confirmed using Fourier spectroscopy and third-harmonic generation methods [2,3]. We also discussed applications of the developed laser-printed plasmonic platforms for optical nano-sensing and enhancing/shaping the spontaneous emission of the coupled HgTe quantum dots with photoluminescence yield at near-IR wavelengths matching the qBIC mode spectral position [4].
Figure 1. (a) SEM image of the nanobump arrays (bottom inset: cross-section cut revealing hollow structure of the bumps). (b) Measured and calculated reflectance spectra of the nanobump array. (c) Schematic illustration of the device of tailoring PL properties of the HgTe QDs as well as (d) PL spectra of the QDs monolayers depending on the spectral position of the qBIC mode supported by the device.
The work was supported by Russian Science Foundation (project No. 24-19-00541)
[1] A. Sergeev, et al, Tailoring spontaneous infrared emission of HgTe quantum dots with laser-printed plasmonic arrays. Light: Science & Applications 9 (1), 16 (2020).
[2] D. Pavlov, et al, Tuning collective plasmon resonances of femtosecond laser-printed metasurface. Materials 15 (5), 1834 (2022).
[3] A.B. Cherepakhin, et al, Laser-printed hollow nanostructures for nonlinear plasmonics, Applied Physics Letters 117 (4) (2020).
[4] K. Sergeeva, et al, Laser-Printed Plasmonic Metasurface Supporting Bound States in the Continuum Enhances and Shapes Infrared Spontaneous Emission of Coupled HgTe Quantum Dots, Advanced Functional Materials 33 (44), 2307660 (2023).
