  Conventional plasmonic nanoantennas enable scattering and absorption bands at
the same wavelength region, making their utilization to full potential
impossible for both features simultaneously. In this regard, hyperbolic
meta-antennas (HMA) offer independent, tunable and separate scattering and
absorption resonance bands at different spectral ranges. Here, we take
advantage of these separated spectral bands in HMA to enhance and modify the
hot electron-based phenomena. On the one hand, we observed the photoexcited
emission of particle plasmons by hot carriers; on the other, we utilized
ultrafast transient absorption spectroscopy to characterize the dynamics of hot
electrons. Compared to corresponding plasmonic nanodisk antennas (NDA),
extended plasmon-modulated photoluminescence (PM-PL) spectrum in HMA is
achieved, attributing to their particular scattering spectra. Furthermore, the
absorption band at longer wavelengths in HMA enhances the excitation efficiency
of plasmon-induced hot electrons (HEs) in the near-infrared region (NIR) with
an extended lifetime. It broadens the utilization of the visible/NIR range that
can not be observed in conventional NDAs. Our results further show that such
meta-antennas can generate plasmon-induced hot carriers on demand and provide
insight into the optimization and engineering of the hot-carrier-assisted
photochemistry.
