Large-radius nanowire based hybrid plasmonic nanolasers

Hybrid plasmonic lasers in nanowires of small size have been intensively studied in the past few years. However, there is a condition, which is that the size of the nanowire should be small enough (diameter ∼ 100 nm) to suppress the lasing of the photonic modes. Because the photonic modes suffer less loss, leading to lower threshold. Thus for large-size nanowires, it is hard to achieve the lasing of plasmonic modes. Here we study the lasing actions in larger-radius nanowire based hybrid plasmonic nanostructure and explore the possibility of reducing the thresholds of spasers. We have successfully observed hybrid plasmonic nanolasers at room temperature by placing CdS nanowires onto SiO
2
coated Ag film, even though the diameters of CdS nanowires are similar to or even larger than the lasing wavelengths. Most importantly, while the effective mode volumes of plasmonic lasers are kept on the nanoscale, their thresholds become comparable to photonic lasers for the first time. The photonic modes are strongly scattered by the nanoparticles and suppressed, whereas the plasmonic modes take most of the amplifications and lase. We believe that our research will be important to improve the performances of hybrid plasmonic nanolasers.