Plasmonic-induced self-assembly of WGM cavities via laser cavitation
| Autor: | Ken Takazawa, Rodrigo Sato, Joel Henzie, Yoshihiko Takeda, Satoshi Ishii |
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| Rok vydání: | 2020 |
| Předmět: |
Materials science
Active laser medium business.industry Physics::Optics 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Atomic and Molecular Physics and Optics 010309 optics Optical pumping Resonator Optics 0103 physical sciences Optoelectronics Whispering-gallery wave Surface plasmon resonance 0210 nano-technology business Lasing threshold Free spectral range Plasmon |
| Zdroj: | Optics express. 28(21) |
| ISSN: | 1094-4087 |
| Popis: | We show how photoexcitation of a single plasmonic nanoparticle (NP) in solution can create a whispering-gallery-mode (WGM) droplet resonator. Small nano/microbubbles are initially formed by laser-induced heating that is localized by the plasmon resonance. Fast imaging shows that the bubbles collect and condense around the NP and form a droplet in the interior of the bubble. Droplets containing dye generated lasing modes with wavelengths that depend on the size of the droplet, refractive index of the solvent, and surrounding environment, matching the behavior of a WGM. We demonstrated this phenomenon with two kinds of Au NPs in addition to TiN NPs and observed cavity diameters as small as 4.8 µm with a free spectral range (FSR) of 12 nm. These results indicate that optical pumping of plasmonic NPs in a gain medium can generate lasing modes that are not directly associated with the plasmon cavity but can arise from its photophysical processes. This process may serve as a method to generate plasmonic/photonic optical microcavities in solution on demand at any location in a solvent using free-space coupling in/out of the cavity. |
| Databáze: | OpenAIRE |
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