Silver Nanoparticle Chains for Ultra-Long-Range Plasmonic Waveguides for Nd3+ Fluorescence

Abstract

Plasmonic waveguides have been shown to be a promising approach to confine and transport electromagnetic energy beyond the diffraction limit. However, ohmic losses generally prevent their integration at micrometric or millimetric scales. Here, we present a gain-compensated plasmonic waveguide based on the integration of linear chains of Ag nanoparticles on an optically active Nd3+-doped solid-state gain medium. By means of dual confocal fluorescence microscopy, we demonstrate long-range optical energy propagation due to the near-field coupling between the plasmonic nanostructures and the Nd3+ ions. The subwavelength fluorescence guiding is monitored at distances of around 100 µm from the excitation source for two different emission ranges centered at around 900 nm and 1080 nm. In both cases, the guided fluorescence exhibits a strong polarization dependence, consistent with the polarization behavior of the plasmon resonance supported by the chain. The experimental results are interpreted through numerical simulations in quasi-infinite long chains, which corroborate the propagation features of the Ag nanoparticle chains at both excitation (λexc = 590 nm) and emission wavelengths. The obtained results exceed by an order of magnitude that of previous reports on electromagnetic energy transport using linear plasmonic chains. The work points out the potential of combining Ag nanoparticle chains with a small interparticle distance (~2 nm) with rare-earth-based optical gain media as ultra-long-range waveguides with extreme light confinement. The results offer new perspectives for the design of integrated hybrid plasmonic–photonic circuits based on rare-earth-activated solid-state platforms.

Editorial of the Special Issue ‘Nano-Optics and Nano-Optoelectronics: Challenges and Future Trends’

“…To explore the latest developments and challenges and the future trends in nano-optics and nano-optoelectronics, this Special Issue compiles sixteen papers dedicated to very recent advances in nanostructures and nanomaterials. In these papers, novel nanostructures and nanomaterials, such as metastructures [ 1 , 2 , 3 ], metalenses [ 4 , 5 ], nanoparticles [ 6 , 7 ], layered 2D materials [ 8 , 9 ], and nano-semiconductors [ 10 , 11 ], are presented in detail. Due to their exceptional properties, these nanostructures/nanomaterials offer a diverse range of novel applications in photodetectors [ 1 , 9 , 11 ], solar cells [ 2 , 9 , 10 ], modulators [ 1 , 3 , 8 ], light emitters [ 1 , 7 ], optoelectronic integration [ 5 , 6 ], super-resolved imaging [ 4 , 5 ], nanofabrication [ 4 ], etc.…”

“…In these papers, novel nanostructures and nanomaterials, such as metastructures [ 1 , 2 , 3 ], metalenses [ 4 , 5 ], nanoparticles [ 6 , 7 ], layered 2D materials [ 8 , 9 ], and nano-semiconductors [ 10 , 11 ], are presented in detail. Due to their exceptional properties, these nanostructures/nanomaterials offer a diverse range of novel applications in photodetectors [ 1 , 9 , 11 ], solar cells [ 2 , 9 , 10 ], modulators [ 1 , 3 , 8 ], light emitters [ 1 , 7 ], optoelectronic integration [ 5 , 6 ], super-resolved imaging [ 4 , 5 ], nanofabrication [ 4 ], etc. This Special Issue also encompasses the latest advancements in practical nano-optical and nano-optoelectronic technologies, such as femtosecond laser nano-processing [ 12 ], atomic layer coating [ 13 ], and new designs for photonic integration engineering [ 14 ].…”

“…Nanoparticles or quantum dots, as the 2023 Nobel Prize for Chemistry proved, have found a key role in optoelectronics and are worthy of further exploration within nanotechnology. Fernández-Martínez et al [ 6 ] present a gain-compensated plasmonic waveguide that integrates linear chains of Ag nanoparticles on an optically active Nd 3+ -doped solid-state gain medium. Their experiments demonstrated a significant improvement in electromagnetic energy transport, and they offer new perspectives on integrated hybrid plasmonic–photonic circuits based on quantum dot platforms.…”