Tunable Transient Mid‐Infrared Plasmonics in Germanium Nanowires

This is the authors' abstract. We don't add key points for this paper.

Transient plasmonic quasiparticles in semiconductors, activated by photogenerated carriers, enable ultrafast light manipulation at the nanoscale. Here, we focus on creating and manipulating robust transient plasmons in germanium (Ge) nanowires, a model indirect bandgap semiconductor that provides an ideal platform for exploring non‐equilibrium dynamics and emergent optical properties under optical excitation. Using state‐of‐the‐art near‐field spectroscopic analysis and real‐space optical imaging, we uncover the transient plasmonic behavior of Ge nanowires characterized by carrier dynamics. Our results demonstrate that transient plasmons in Ge nanowires achieve a spectral tuning range exceeding 1000 cm −1 , together with a prolonged lifetime exceeding 7.2 picoseconds (ps). These findings highlight the potential of optical pumping as a versatile and powerful tool for generating and controlling quasiparticles in indirect bandgap semiconductors.