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arXiv · 2609.28375

Lasing Mode Control in ZnO Nanowires Coupled to TiO2 Nanopillars

Daniel Repp·Francesco Vitale·Raja Hoffmann·Isabelle Staude·Thomas Siefke·Carsten Ronning·Thomas Pertsch
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Abstract

Nanowire lasers based on spectrally broad gain materials typically exhibit multimode emission, which limits their utility in applications requiring precisely defined spectral characteristics. In this study, we experimentally demonstrate the selective, narrow-band suppression of individual lasing modes in zinc oxide (ZnO) nanowire lasers through near-field coupling to titania (TiO2) nanopillars. Our study is based on photoluminescence spectroscopy in the lasing regime, which is complemented by finite-difference time-domain simulations. We show suppression of longitudinal nanowire lasing modes by their resonant coupling to the whispering gallery modes in nanopillars of suitable size. In addition to spectral selectivity of the coupling, we reveal two distinct coupling regimes based on polarization matching between whispering gallery modes and nanowire waveguide modes. These findings demonstrate a promising approach towards engineering the spectral emission properties of nanowire lasers through tailored photonic architectures.

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Daniel Repp, Francesco Vitale, Raja Hoffmann, Isabelle Staude, Thomas Siefke, Carsten Ronning, Thomas Pertsch. 2026-09-23. Lasing Mode Control in ZnO Nanowires Coupled to TiO2 Nanopillars. https://arxiv.org/abs/2609.28375

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