https://doi.org/10.1140/epjp/s13360-026-07465-3
Regular Article
Enhanced visible light emission and reduced lasing threshold in R6G gain medium coupled with optimized silver bowtie array using surface lattice resonance
Department of Physics, Faculty of Science, Lorestan University, Khorramabad, Iran
a
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Received:
16
September
2025
Accepted:
20
February
2026
Published online:
6
April
2026
Abstract
With the advancements in optical technologies, the development of coherent micro- and nanoscale light sources with low energy consumption has become essential. This study presents the design and optimization of a plasmonic nanolaser based on a periodic array of silver bowtie nanoparticles embedded in a rhodamine (R6G) gain medium, utilizing finite-difference time-domain (FDTD) simulations to achieve enhanced visible light emission and a low lasing threshold. By systematically optimizing the gain medium thickness (150 nm), molecular concentration (1.85 × 1025 m⁻3), array period (375 nm), and bowtie geometry (40 nm thickness, 200 nm height, 310 nm base length), surface lattice resonance (SLR) modes are selectively excited to generate strong localized optical fields and enhance plasmon–gain coupling. The optimized structure achieves a significantly reduced lasing threshold of 1.65 
and a narrow spectral linewidth of 0.41 nm at 569 nm, demonstrating a clear transition from spontaneous to coherent emission. These results highlight the critical role of SLR in mitigating ohmic losses and improving spatial coherence in plasmonic nanolasers, advancing the development of low-threshold, visible-range coherent sources for integrated photonics and nano-optoelectronic devices.
Supplementary Information The online version contains supplementary material available at https://doi.org/10.1140/epjp/s13360-026-07465-3.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2026
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
